KR102622150B1 - Bidirectional inter-frame prediction method and device - Google Patents

Abstract

Embodiments of the present application relate to the field of video picture coding technology, and disclose a bidirectional inter prediction method and apparatus for improving coding efficiency. The method includes obtaining instruction information, wherein the instruction information is used to instruct determining second motion information based on first motion information, and the first motion information is motion information of the current picture block in the first direction. , and the second motion information is motion information of the current picture block in the second direction -; determining second motion information based on the first motion information; and determining a prediction sample of the current picture block based on the first motion information and the second motion information.

Description

BIDIRECTIONAL INTER-FRAME PREDICTION METHOD AND DEVICE}

This application claims priority from Chinese Patent Application No. 201810274457.

Embodiments of the present application relate to the field of video picture coding technology, and specifically to a bidirectional inter prediction method and apparatus.

In video coding techniques, the predicted picture block of the current picture block is generated based on only one reference picture block (called one-way inter prediction), or the predicted picture block of the current picture block is generated based on at least two reference picture blocks. can be generated (called two-way inter prediction). The at least two reference picture blocks may be from the same reference frame or different reference frames.

In order for the decoder and encoder to use the same reference picture block, the encoder must send the motion information of each picture block in the bitstream to the decoder. Generally, motion information of the current picture block includes a reference frame index value, a motion vector predictor (MVP) flag, and a motion vector difference (MVD). The decoder can find the correct reference picture block within the selected reference frame based on its reference frame index value, MVP flag, and MVD.

Accordingly, in bidirectional inter prediction, the encoder must send motion information of each picture block in each direction to the decoder. As a result, motion information occupies relatively large transmission resources. This reduces effective use of transmission resources, transmission rate, and coding compression efficiency.

Embodiments of the present application provide a bidirectional inter-prediction method and device to solve the problem that effective utilization of transmission resources, transmission rate, and coding compression efficiency are reduced due to motion information occupying relatively large transmission resources.

Embodiments of the present application provide a bidirectional inter-prediction method and device to solve the problem that effective utilization of transmission resources, transmission rate, and coding compression efficiency are reduced due to motion information occupying relatively large transmission resources.

In order to achieve the above-mentioned objectives, the following technical solutions are used in the embodiments of the present application.

According to a first aspect, a bidirectional inter prediction method is provided. The method includes: obtaining instruction information used to instruct to determine second motion information based on first motion information, wherein the first motion information is motion information of the current picture block in the first direction, and second The motion information is motion information of the current picture block in the second direction -; Obtaining first motion information; determining second motion information based on the obtained first motion information; and determining a prediction sample of the current picture block based on the obtained first motion information and the determined second motion information.

According to the bidirectional inter prediction method provided in the present application, after the indication information is obtained, the second motion information is determined based on the first motion information. In this way, the bitstream only needs to contain indication information and first motion information, and no longer needs to contain second motion information. Compared to the prior art in which the bitstream includes motion information of each picture block in each direction, the bidirectional inter prediction method provided in the present application effectively reduces the motion information included in the bitstream, effectively utilizes transmission resources, and improves the transmission rate. and improves the coding rate.

Optionally, in a possible implementation of the present application, the method for “determining second motion information based on the first motion information” includes: obtaining an index value of the first reference frame in the first motion information; 1 determining the sequence number of the first reference frame based on the index value of the reference frame and the first reference frame list, where the first reference frame is a reference frame of the current picture block in the first direction, and The index value is the number of the first reference frame in the first reference frame list -; Obtaining an index value of a second reference frame, and determining a sequence number of the second reference frame based on the index value of the second reference frame and the second reference frame list, wherein the second reference frame is the current sequence number in the second direction. It is a reference frame of a picture block, and the index value of the second reference frame is the number of the second reference frame in the second reference frame list -; determining a first motion vector based on the first motion vector predictor flag and the first motion vector difference in the first motion information, where the first motion vector is the motion vector of the current picture block in the first direction; and the following formula:

It includes deriving a second motion vector within the second motion information according to.

In the above formula, mv_IY represents the second motion vector, POC_Cur represents the sequence number of the current frame, POC_listX represents the sequence number of the first reference frame, POC_listY represents the sequence number of the second reference frame, and mv_IX represents the sequence number of the first reference frame. Indicates 1 motion vector, and the second motion vector is the motion vector of the current picture block in the second direction.

Optionally, in another possible implementation of the present application, the method for “determining second motion information based on first motion information” includes: obtaining an index value of the first reference frame from the first motion information. Step - the first reference frame is the reference frame of the current picture block in the first direction, and the index value of the first reference frame is the number of the first reference frame in the first reference frame list; Obtaining an index value of a second reference frame - the second reference frame is a reference frame of the current picture block in the second direction, and the index value of the second reference frame is the number of the second reference frame in the second reference frame list. lim -; determining a first motion vector based on the first motion vector predictor flag and the first motion vector difference in the first motion information, where the first motion vector is the motion vector of the current picture block in the first direction; and when the first reference frame is a forward reference frame of the current picture block and the second reference frame is a backward reference frame of the current picture block, or if the first reference frame is a backward reference frame of the current picture block a reference frame and the second reference frame is a forward reference frame of the current picture block, or the first reference frame and the second reference frame are each a forward reference frame of the current picture block, or the first reference frame and the second reference frame If each is a reverse reference frame of the current picture block, the following formula:

It includes deriving a second motion vector within the second motion information according to.

In this formula, mv_IY represents the second motion vector, mv_IX represents the first motion vector, and the second motion vector is the motion vector of the current picture block in the second direction.

“The first reference frame is a forward reference frame of the current picture block and the second reference frame is a backward reference frame of the current picture block” and “The first reference frame is a backward reference frame of the current picture block and the second reference frame is "is the forward reference frame of the current picture block" both,

formula It is expressed as, or a formula It can be expressed as

In addition, both "the first reference frame and the second reference frame are each a forward reference frame of the current picture block" and "the first reference frame and the second reference frame are each a backward reference frame of the current picture block", formula It can be expressed as

POC_Cur represents the sequence number of the current frame, POC_listX represents the sequence number of the first reference frame, and POC_listY represents the sequence number of the second reference frame.

Optionally, in another possible implementation of the present application, the method for “determining second motion information based on the first motion information” includes: a first motion vector difference within the first motion information and a first reference Obtaining an index value of a frame, and determining a sequence number of a first reference frame based on the index value of the first reference frame and the first reference frame list, wherein the first reference frame is an index value of the current picture block in the first direction. It is a reference frame, and the index value of the first reference frame is the number of the first reference frame in the first reference frame list -; Obtain the index value of the second reference frame, determine the sequence number of the second reference frame based on the index value of the second reference frame and the second reference frame list, and calculate the index value of the second reference frame and the second candidate prediction. Determining a second predicted motion vector based on the candidate predicted motion vector list - the second predicted motion vector is the predicted motion vector of the current picture block in the second direction. and the second reference frame is a reference frame of the current picture block in the second direction, and the index value of the second reference frame is the number of the second reference frame in the second reference frame list. The following formula:

Accordingly, calculating a second motion vector difference in the second motion information - where mvd_IY represents the second motion vector difference, POC_Cur represents the sequence number of the current frame, and POC_listX represents the sequence number of the first reference frame. indicates, POC_listY indicates the sequence number of the second reference frame, and mvd_IX indicates the first motion vector difference -; and determining a second motion vector based on the second predicted motion vector and the second motion vector difference, wherein the second motion vector is a motion vector of the current picture block in the second direction.

Optionally, in another possible implementation of the present application, the method for “determining second motion information based on the first motion information” includes: a first motion vector within the first motion information and a first reference frame; obtaining an index value of - the first reference frame is a reference frame of the current picture block in the first direction, and the index value of the first reference frame is the number of the first reference frame in the first reference frame list; Obtaining an index value of a second reference frame, and determining a second predicted motion vector based on the index value of the second reference frame and the second candidate predicted motion vector list, wherein the second predicted motion vector is the second predicted motion vector. is the predicted motion vector of the current picture block in the direction, the second reference frame is the reference frame of the current picture block in the second direction, and the index value of the second reference frame is the index of the second reference frame in the second reference frame list. Number -; If the first reference frame is a forward reference frame of the current picture block and the second reference frame is a backward reference frame of the current picture block, or if the first reference frame is a backward reference frame of the current picture block and the second reference frame is a backward reference frame of the current picture block is a forward reference frame of, or if the first reference frame and the second reference frame are each a forward reference frame of the current picture block, or if the first reference frame and the second reference frame are each a backward reference frame of the current picture block. , the following formula:

calculating a second motion vector difference in the second motion information according to where mvd_IY represents the second motion vector difference and mvd_IX represents the first motion vector difference; and determining a second motion vector based on the second predicted motion vector and the second motion vector difference, wherein the second motion vector is a motion vector of the current picture block in the second direction.

Likewise,

“The first reference frame is a forward reference frame of the current picture block and the second reference frame is a backward reference frame of the current picture block” and “The first reference frame is a backward reference frame of the current picture block and the second reference frame is "is the forward reference frame of the current picture block" both,

formula It is expressed as, or a formula It can be expressed as This is not specifically limited in this application.

Both “the first reference frame and the second reference frame are each a forward reference frame of the current picture block” and “the first reference frame and the second reference frame are each a backward reference frame of the current picture block”, the formula It can be expressed as

POC_Cur represents the sequence number of the current frame, POC_listX represents the sequence number of the first reference frame, and POC_listY represents the sequence number of the second reference frame.

The bi-directional inter prediction method provided by this application is: determining a second motion vector based on a first motion vector, or determining a second motion vector difference based on the first motion vector difference and determining the second motion vector The second motion vector may be determined based on the difference.

Optionally, in another possible implementation of the present application, the method for “obtaining the index value of the second reference frame” is: Accordingly, calculating a first sequence number based on the sequence number of the current frame and the sequence number of the first reference frame, where POC_Cur represents the sequence number of the current frame and POC_listX represents the sequence number of the first reference frame. represents, and POC_listY0 represents the first sequence number -; And when the second reference frame list includes the first sequence number, determining the number of the reference frame indicated by the first sequence number in the second reference frame list as the index value of the second reference frame.

Optionally, in another possible implementation of the present application, the method for “obtaining the index value of the second reference frame” is: calculating a second sequence number based on the sequence number of the current frame and the sequence number of the first reference frame, wherein: represents the second sequence number -; And when the second reference frame list includes the second sequence number, determining the number of the reference frame indicated by the second sequence number in the second reference frame list as the index value of the second reference frame.

Optionally, in another possible implementation of the present application, the method for “obtaining the index value of the second reference frame” is: Accordingly, calculating a third sequence number based on the sequence number of the first reference frame and the sequence number of the current frame, wherein: is the third sequence number -; and determining, as an index value of the second reference frame, the number of the reference frame indicated by the third sequence number in the second reference frame list.

Optionally, in another possible implementation of the present application, the method for “obtaining the index value of the second reference frame” is: Accordingly, the first sequence number is calculated based on the sequence number of the first reference frame and the sequence number of the current frame, POC_Cur represents the sequence number of the current frame, POC_listX represents the sequence number of the first reference frame, and POC_listY0 represents the first sequence number. When the second reference frame list includes the first sequence number, the number of the reference frame indicated by the second sequence number in the second reference frame is determined as the index value of the second reference frame. If the second reference frame list does not contain the first sequence number, the second sequence number is Calculated based on the sequence number of the first reference frame and the sequence number of the current frame, represents the second sequence number. When the second reference frame list includes a second reference number, the number of the reference frame indicated by the second sequence number in the second reference frame list is determined as the index value of the second reference frame. If the second reference frame list does not contain the second sequence number, the third sequence number is is calculated based on the sequence number of the first reference frame and the sequence number of the current frame, is the third sequence number, and the number of the reference frame indicated by the third sequence number in the second reference frame list is determined as the index value of the second reference frame.

Optionally, in another possible implementation of the present application, the method for “obtaining the index value of the second reference frame” is to obtain the index value of the second reference frame by parsing the bitstream.

It can be seen that there may be several methods for “obtaining the index value of the second reference frame” in this application. The specific method used to obtain the index value of the second reference frame may be determined according to actual requirements or may be set in advance.

According to a second aspect, a bidirectional inter prediction device is provided. The bidirectional inter prediction device includes an acquisition unit and a decision unit.

Specifically, the acquisition unit is configured to acquire instruction information and obtain first motion information, the instruction information is used to instruct to determine the second motion information based on the first motion information, and the first motion information is used to determine the second motion information. This is motion information of the current picture block in the first direction, and the second motion information is motion information of the current picture block in the second direction. The determination unit is configured to determine the second motion information based on the first motion information obtained by the acquisition unit, and determine the prediction sample of the current picture block based on the first motion information and the second motion information.

Optionally, in a possible implementation of the present application, the decision unit specifically obtains the index value of the first reference frame in the first motion information and makes the first reference frame based on the index value of the first reference frame and the first reference frame list. 1 Determine the sequence number of the reference frame, wherein the first reference frame is a reference frame of the current picture block in the first direction, and the index value of the first reference frame is the number of the first reference frame in the first reference frame list. ; Obtain the index value of the second reference frame, and determine the sequence number of the second reference frame based on the index value of the second reference frame and the second reference frame list, wherein the second reference frame is the current picture in the second direction. It is a reference frame of a block, and the index value of the second reference frame is the number of the second reference frame in the second reference frame list -; determine a first motion vector based on the first motion vector predictor flag and the first motion vector difference in the first motion information, where the first motion vector is the motion vector of the current picture block in the first direction; And the following formula:

Configured to derive a second motion vector in the second motion information according to,

Here, mv_IY represents the second motion vector, POC_Cur represents the sequence number of the current frame, POC_listX represents the sequence number of the first reference frame, POC_listY represents the sequence number of the second reference frame, and mv_IX represents the first motion represents a vector, and the second motion vector is the motion vector of the current picture block in the second direction.

Optionally, in another implementation of the present application, the decision unit specifically obtains an index value of a first reference frame in the first motion information, wherein the first reference frame is a reference frame of the current picture block in the first direction. , and the index value of the first reference frame is the number of the first reference frame in the first reference frame list -; Obtain the index value of the second reference frame - the second reference frame is the reference frame of the current picture block in the second direction, and the index value of the second reference frame is the number of the second reference frame in the second reference frame list. -; determine a first motion vector based on the first motion vector predictor flag and the first motion vector difference in the first motion information, where the first motion vector is the motion vector of the current picture block in the first direction; and when the first reference frame is a forward reference frame of the current picture block and the second reference frame is a backward reference frame of the current picture block, or if the first reference frame is a backward reference frame of the current picture block a reference frame and the second reference frame is a forward reference frame of the current picture block, or the first reference frame and the second reference frame are each a forward reference frame of the current picture block, or the first reference frame and the second reference frame If each is a reverse reference frame of the current picture block, the following formula:

and configured to derive a second motion vector in the second motion information according to, where mv_IY represents the second motion vector, mv_IX represents the first motion vector, and the second motion vector is the current picture block in the second direction. is the motion vector of .

Optionally, in another possible implementation of the present application, the determination unit specifically obtains the first motion vector difference in the first motion information and the index value of the first reference frame, the index value of the first reference frame and Determine the sequence number of the first reference frame based on the first reference frame list, wherein the first reference frame is a reference frame of the current picture block in the first direction, and the index value of the first reference frame is the first reference frame list. Is the number of the first reference frame within -; Obtain the index value of the second reference frame, determine the sequence number of the second reference frame based on the index value of the second reference frame and the second reference frame list, and calculate the index value of the second reference frame and the second candidate prediction. Determine a second predicted motion vector based on the motion vector list, wherein the second predicted motion vector is the predicted motion vector of the current picture block in the second direction, and the second reference frame is the predicted motion vector of the current picture block in the second direction. It is a reference frame of a picture block, and the index value of the second reference frame is the number of the second reference frame in the second reference frame list -; The following formula:

Accordingly, calculate the second motion vector difference in the second motion information - where mvd_IY represents the second motion vector difference, POC_Cur represents the sequence number of the current frame, and POC_listX represents the sequence number of the first reference frame. , POC_listY represents the sequence number of the second reference frame, mvd_IX represents the first motion vector difference -; and determine a second motion vector based on the second predicted motion vector and the second motion vector difference, where the second motion vector is a motion vector of the current picture block in the second direction.

Optionally, in another possible implementation of the present application, the decision unit specifically obtains an index value of a first motion vector and a first reference frame in the first motion information, wherein the first reference frame is in the first direction. is the reference frame of the current picture block, and the index value of the first reference frame is the number of the first reference frame in the first reference frame list -; Obtain an index value of the second reference frame, and determine a second predicted motion vector based on the index value of the second reference frame and the second candidate predicted motion vector list, wherein the second predicted motion vector is in the second direction. is the predicted motion vector of the current picture block in, the second reference frame is the reference frame of the current picture block in the second direction, and the index value of the second reference frame is the number of the second reference frame in the second reference frame list. lim -; If the first reference frame is a forward reference frame of the current picture block and the second reference frame is a backward reference frame of the current picture block, or if the first reference frame is a backward reference frame of the current picture block and the second reference frame is a backward reference frame of the current picture block is a forward reference frame of, or if the first reference frame and the second reference frame are each a forward reference frame of the current picture block, or if the first reference frame and the second reference frame are each a backward reference frame of the current picture block. , the following formula:

Calculate a second motion vector difference from the second motion information according to - where mvd_IY represents the second motion vector difference, and mvd_IX represents the first motion vector difference -; and determine a second motion vector based on the second predicted motion vector and the second motion vector difference, where the second motion vector is a motion vector of the current picture block in the second direction.

Optionally, in another possible implementation of the present application, the acquisition unit specifically has the formula: Accordingly, calculate the first sequence number based on the sequence number of the current frame and the sequence number of the first reference frame - where POC_Cur represents the sequence number of the current frame, POC_listX represents the sequence number of the first reference frame, and , POC_listY0 indicates the first sequence number -; And when the second reference frame list includes the first sequence number, it is configured to determine, as an index value of the second reference frame, the number of the reference frame indicated by the first sequence number in the second reference frame list.

Optionally, in another possible implementation of the present application, the acquisition unit specifically has the formula: Calculate a second sequence number based on the sequence number of the current frame and the sequence number of the first reference frame according to - where: represents the second sequence number -; And when the second reference frame list includes the second sequence number, it is configured to determine, as an index value of the second reference frame, the number of the reference frame indicated by the second sequence number in the second reference frame list.

Optionally, in another possible implementation of the present application, the acquisition unit specifically has the formula: Accordingly, a third sequence number is calculated based on the sequence number of the first reference frame and the sequence number of the current frame, where: is the third sequence number -; And, as an index value of the second reference frame, it is configured to determine the number of the reference frame indicated by the third sequence number in the second reference frame list.

According to a third aspect, a bidirectional inter prediction method is provided. There are several implementation examples for bidirectional inter prediction methods.

One implementation includes parsing a bitstream to obtain a first identifier - the first identifier is used to indicate whether to determine second motion information based on the first motion information, and the first motion information is used to indicate whether to determine the second motion information based on the first motion information. It is motion information of the current picture block in the direction, and the second motion information is motion information of the current picture block in the second direction -; If the value of the first identifier is a preset first value, first motion information is acquired, and second motion information is acquired based on the first motion information; And prediction samples of the current picture block are determined based on the first motion information and the second motion information.

Another implementation includes parsing the bitstream to obtain a second identifier, where the second identifier is used to indicate whether to calculate motion information of the current picture block using a motion information derivation algorithm; If the value of the second identifier is a preset second value, a third identifier is obtained - the third identifier is used to indicate whether to determine the second motion information based on the first motion information, and the first motion information is used to determine the first motion information. It is motion information of the current picture block in the direction, and the second motion information is motion information of the current picture block in the second direction -; If the value of the third identifier is a preset third value, first motion information is acquired, and second motion information is acquired based on the first motion information; And the prediction sample of the current picture block is determined based on the first motion information and the second motion information.

Another implementation includes parsing the bitstream to obtain a second identifier, where the second identifier is used to indicate whether to calculate motion information of the current picture block using a motion information derivation algorithm; If the value of the second identifier is a preset second value, first motion information is obtained, and second motion information is obtained based on the first motion information - the first motion information is the current picture block in the first direction. It is motion information, and the second motion information is motion information of the current picture block in the second direction -; And the prediction sample of the current picture block is determined based on the first motion information and the second motion information.

Another implementation includes parsing the bitstream to obtain a fourth identifier, where the fourth identifier is used to indicate whether to calculate motion information of the current picture block using a motion information derivation algorithm; If the value of the fourth identifier is a preset fourth value, the index value of the first reference frame and the index value of the second reference frame are determined based on the first reference frame list and the second reference frame list - the first reference frame The list is a list of reference frames of the current picture block in the first direction, the second reference frame list is the list of reference frames of the current picture block in the second direction, and the first reference frame is the list of reference frames of the current picture block in the first direction. is a reference frame, and the second reference frame is a reference frame of the current picture block in the second direction -; Obtain a first motion vector difference and a first motion vector predictor flag, and determine second motion information based on the first motion information, where the first motion information includes an index value of the first reference frame, the first motion vector difference, , and a first motion vector predictor flag, wherein the second motion information is motion information of the current picture block in the second direction; and determining a prediction sample of the current picture block based on the first motion information and the second motion information.

Another implementation includes parsing the bitstream to obtain a first identifier, wherein the first identifier is used to indicate whether to determine second motion information based on the first motion information, and the first motion information is used in the first direction. is motion information of the current picture block, and the second motion information is motion information of the current picture block in the second direction -; If the value of the first identifier is a preset eighth value, obtain a fifth identifier - the fifth identifier is used to indicate whether to determine the first motion information based on the second motion information -; If the fifth identifier is a preset fifth value, obtain second motion information and determine first motion information based on the second motion information; And the prediction sample of the current picture block is determined based on the first motion information and the second motion information.

Another implementation includes parsing the bitstream to obtain a second identifier - the second identifier is used to indicate whether to calculate motion information of the current picture block using a motion information derivation algorithm; If the second identifier is a preset second value, obtain a third identifier - the third identifier is used to indicate whether to determine the second motion information based on the first motion information, and the first motion information is used in the first direction. is motion information of the current picture block, and the second motion information is motion information of the current picture block in the second direction -; If the value of the third identifier is a preset sixth value, obtain second motion information and determine first motion information based on the second motion information; And the prediction sample of the current picture block is determined based on the first motion information and the second motion information.

For detailed descriptions of the first to fourth identifiers, please refer to the following.

In the bidirectional inter prediction method provided in this application, after parsing a bitstream to obtain an identifier, whether to determine the second motion information based on the first motion information is determined based on the value of the identifier. After it is determined that the second motion information should be determined based on the first motion information, the first motion information is obtained, and then the second motion information is determined based on the obtained first motion information. In this way, the bitstream only needs to include the corresponding identifier and first motion information, and no longer needs to include the second motion information. Compared to the prior art in which the bitstream includes motion information of each picture block in each direction, the bi-directional inter prediction method provided in the present application effectively reduces the motion information included in the bitstream, effectively utilizes transmission resources, and improves the transmission rate. and improves the coding rate.

According to a fourth aspect, a bidirectional inter prediction device is provided. This bi-directional inter prediction device includes an acquisition unit and a decision unit.

Specifically, in one implementation, the acquisition unit is configured to parse a bitstream to obtain a first identifier, and if the value of the first identifier is a preset first value, obtain first motion information; The first identifier is used to indicate whether to determine the second motion information based on the first motion information, the first motion information is motion information of the current picture block in the first direction, and the second motion information is in the second direction. This is the motion information of the current picture block. The determination unit determines the second motion information based on the first motion information obtained by the acquisition unit, and determines prediction samples of the current picture block based on the first motion information and the second motion information. It is composed.

In another implementation, the acquisition unit acquires a second identifier by parsing the bitstream, and if the value of the second identifier is a preset second value, obtain a third identifier, and if the value of the third identifier is a preset second value, the acquisition unit acquires a second identifier. If it is a third value, it is configured to obtain first motion information, the second identifier is used to indicate whether to calculate motion information of the current picture block using a motion information derivation algorithm, and the third identifier is used to indicate whether to calculate motion information of the current picture block. It is used to indicate whether to determine second motion information based on the first motion information, the first motion information is motion information of the current picture block in the first direction, and the second motion information is the current picture block in the second direction. This is the movement information. The determination unit is configured to determine the second motion information based on the first motion information obtained by the acquisition unit, and determine the prediction sample of the current picture block based on the first motion information and the second motion information.

In another implementation, the acquisition unit is configured to parse the bitstream to obtain a second identifier, and if the value of the second identifier is a preset second value, obtain the first motion information, and the second identifier is the motion information. It is used to indicate whether to calculate the motion information of the current picture block using the derivation algorithm. The determination unit is configured to determine the second motion information based on the first motion information obtained by the acquisition unit, and determine the prediction sample of the current picture block based on the first motion information and the second motion information, 1 motion information is motion information of the current picture block in the first direction, and second motion information is motion information of the current picture block in the second direction.

In another implementation, the acquisition unit is configured to parse the bitstream to obtain a fourth identifier, and the fourth identifier is used to indicate whether to calculate motion information of the current picture block using a motion information derivation algorithm. If the value of the fourth identifier is a preset fourth value, the determination unit is configured to determine the index value of the first reference frame and the index value of the second reference frame based on the first reference frame list and the second reference frame list; , the first reference frame list is a reference frame list of the current picture block in the first direction, the second reference frame list is a reference frame list of the current picture block in the second direction, and the first reference frame is a list of reference frames in the first direction. is the reference frame of the current picture block, and the second reference frame is the reference frame of the current picture block in the second direction. The acquisition unit is further configured to acquire the first motion vector difference and the first motion vector predictor flag. The determination unit is further configured to determine second motion information based on the first motion information, and determine a prediction sample of the current picture block based on the first motion information and the second motion information, and the first motion information is configured to determine the second motion information based on the first motion information. It includes an index value of 1 reference frame, a first motion vector difference, and a first motion vector predictor flag, and the second motion information is motion information of the current picture block in the second direction.

According to the fifth aspect, a terminal is provided. This terminal includes one or more processors, memory, and communication interfaces. Memory and communication interfaces are connected to one or more processors. The memory is configured to store computer program code. Computer program code contains instructions. When one or more processors execute the instruction, the terminal performs the bidirectional inter prediction method according to the first aspect or one of the possible implementations of the first aspect or the third aspect or one of the possible implementations of the third aspect. A two-way inter prediction method according to either one is performed.

According to a seventh aspect, a video decoder is provided, comprising a non-volatile storage medium and a central processing unit. Non-volatile storage media store executable programs. The central processing unit is coupled to a non-volatile storage medium and executes an executable program to perform a bi-directional inter prediction method according to the first aspect or any of the possible implementations of the first aspect or the third aspect or the third aspect. Perform a bidirectional inter prediction method according to any one of the possible implementation examples.

According to a seventh aspect, a decoder is provided. The decoder includes a bidirectional inter prediction device and a reconstruction module in the second side, and the reconstruction module is configured to determine a reconstructed sample value of the current picture block based on prediction samples obtained by the bidirectional inter prediction device. Alternatively, the decoder includes a bidirectional inter prediction device and a reconstruction module in the fourth aspect, and the reconstruction module is configured to determine a reconstructed sample value of the current picture block based on prediction samples obtained by the bidirectional inter prediction device.

According to an eighth aspect, a computer-readable storage medium is provided. A computer-readable storage medium stores instructions. When this instruction is executed in the terminal of the fifth side, this terminal is enabled to perform the bidirectional inter prediction method according to the first side or any of the possible implementations of the first side, or the third side or the third side. Enabled to perform a bi-directional inter prediction method according to any of the possible implementations of the aspect.

According to a ninth aspect, a computer program product including instructions is provided. When the computer program product is executed on a terminal of the fifth aspect, the terminal is enabled to perform the bi-directional inter prediction method according to the first aspect or any of the possible implementations of the first aspect, or the third aspect or the Enabled to perform a bi-directional inter prediction method according to any one of the three possible implementations of the aspect.

In this application, the name of the bidirectional inter prediction device does not impose any restrictions on the device or functional module. In actual implementation, this device or functional module may have a different name. If the function of the device or functional module is similar to the function in the present application, the device or functional module is included in the scope of the claims or equivalents of the present application.

A more detailed description of the fifth to ninth aspects, and embodiments of the fifth to ninth aspects, includes a detailed description of the first aspect and embodiments of the first aspect, or a third aspect or a detailed description of the embodiments of the third aspect. Please refer to the detailed description of the implementation example. In addition, with respect to the fifth to ninth aspects and the beneficial effects to the embodiments of the fifth to ninth aspects, the analysis of the beneficial effects to the embodiments of the first aspect and the first aspect or the third aspect or Reference can be made to the analysis of advantageous effects for the embodiments of the third aspect, so the details will not be described again here.

These and other aspects of the present application will be more concise and easier to understand in the following description.

1 is a schematic structural diagram of a video coding system according to an embodiment of the present application.
Figure 2 is a schematic structural diagram of a video encoder according to an embodiment of the present application.
Figure 3 is a schematic structural diagram of a video decoder according to an embodiment of the present application.
Figure 4 is a schematic flowchart of a bidirectional inter prediction method according to an embodiment of the present application.
Figure 5 is a first schematic structural diagram of a bidirectional inter prediction device according to an embodiment of the present application.
Figure 6 is a second schematic structural diagram of a bidirectional inter prediction device according to an embodiment of the present application.

In the specification, claims, and accompanying drawings of this application, “first,” “second,” “third,” “fourth,” “fifth,” etc. are used to distinguish different objects and do not indicate a specific order. no.

In the embodiments of this application, “example,” “example,” or “for example,” refers to illustration, illustration, or description. None of the embodiments or design schemes described as “examples,” “examples,” or “for example” in the embodiments of the present application should be described as having better advantages or being more preferable than other embodiments or design schemes. Precisely, the use of “example,” “example,” or “for example,” is intended to present related concepts in a specific manner.

To facilitate understanding of the embodiments of the present application, related elements in the embodiments of the present application are first described here.

Picture encoding: The process of compressing a picture sequence into a bitstream.

Picture decoding: The process of reconstructing a bitstream into a reconstructed picture according to specific syntax rules and specific processing methods.

Currently, the video picture encoding process is as follows. First, the encoder divides the frame of the original picture into several non-overlapping parts. Here, each part is used as a picture block. Then, the encoder performs prediction, transformation, and quantization on each picture block to obtain a bitstream corresponding to the picture block. Here, prediction is used to obtain a prediction block of a picture block, thereby reducing transmission overhead by encoding and transmitting only the difference (also called residual or residual block) between a picture block and its prediction block. You can do it. Finally, the encoder sends the bitstream corresponding to the picture block to the decoder.

Correspondingly, after receiving the bitstream, the decoder performs a video decoding process. Specifically, the decoder performs prediction, inverse quantization, and inverse transformation on the received bitstream to obtain a reconstructed picture block (also referred to as a post-reconstruction picture block). This process is also called the picture reconstruction process. Then, the decoder assembles the reconstructed block of each picture block into the original picture to obtain a reconstructed picture of the original picture, and plays the reconstructed picture.

Existing video picture coding techniques include intra prediction and inter prediction. Intra prediction is prediction made by coding/decoding a picture block using the correlation between the current frame and the reference frame of the current frame. The current frame may have one or more reference frames. Specifically, the predicted picture block of the current picture block is generated based on samples within the reference frame of the current picture block.

In general, the prediction picture block of the current picture block may be generated based on only one reference picture block, or the prediction picture block of the current picture block may be generated based on at least two reference picture blocks. Generating a predictive picture block of the current picture block based on a reference picture block is called unidirectional prediction, and generating a predictive picture block of the current picture block based on at least two picture blocks is called bidirectional prediction. In bidirectional inter prediction, at least two reference picture blocks may be from the same reference frame or different reference frames. In other words, “direction” in this application is a generalized definition. In this application, one direction corresponds to one reference picture block. Hereinafter, the first direction and the second direction correspond to different reference picture blocks. The two reference picture blocks may be included in the forward reference frame/backward reference frame of the current picture block. Alternatively, one reference picture block may be included in the forward reference frame of the current picture block, and another reference picture block may be included in the backward reference frame of the current picture block.

Optionally, two-way inter prediction utilizes a correlation between the current video frame and a video frame encoded and played before the current video frame, and a correlation between the current video frame and a video frame encoded before the current video frame and played after the current video frame. It may be inter prediction performed by:

Bidirectional inter prediction includes inter prediction in two directions, commonly referred to as forward inter prediction and backward inter prediction. Forward inter prediction is performed using the correlation between the current video frame and video frames encoded and played prior to the current video frame. Backward inter prediction is performed using the correlation between the current video frame and video frames encoded before the current video frame and played after the current video frame.

Forward inter prediction corresponds to the forward reference frame list L0, and backward inter prediction corresponds to the backward reference frame list L1. The two reference frame lists may contain the same number of reference frames or a different number of reference frames.

Motion compensation (MC: Motion Compensation) is a process of predicting the current picture block using a reference picture block.

In most encoding frameworks, a video sequence contains a series of pictures, and the pictures are partitioned into at least one slice, and each slice is also partitioned into picture blocks. Video encoding/decoding is performed by picture blocks. The encoding/decoding process is performed row by row from left to right and from top to bottom, starting from the upper left corner of the picture. Here, the picture block may be a macro block (MB) in the video coding standard H.264, or a coding unit (CU) in the High Efficiency Video Coding (HEVC) standard. there is. This is not particularly limited in the embodiments of this application.

In this application, the picture block being encoded/decoded is called the current picture block, and the picture in which the current picture block is located is called the current frame.

In general, the current frame may be a one-way prediction frame (P frame) or a two-way prediction frame (B frame). If the current frame is a P frame, the current frame has one reference frame list. When the current frame is a B frame, the current frame has two reference frame lists, and these two lists are usually referred to as L0 and L1, respectively. Each reference frame list includes at least one reconstructed frame that is used as a reference frame for the current frame. This reference frame is used to provide reference samples for inter prediction of the current frame.

In the current frame, neighboring picture blocks of the current picture block (e.g., to the left, above, right of the current block) may have already been encoded/decoded, and a reconstructed picture is obtained. Neighboring picture blocks are also called reconstructed picture blocks. Information such as reconstructed samples and coding mode of the reconstructed picture block becomes available.

A frame encoded/decoded before the current frame is encoded/decoded is called a reconstructed frame.

Motion vector (MV) is an important parameter in the inter prediction process and represents the spatial displacement of the encoded picture block with respect to the current picture block. Typically, a motion vector can be obtained using a motion estimation (ME) method such as motion search. In preliminary inter prediction technology, the encoder transmits the motion vector of the current picture block within the bitstream, thereby causing the decoder to reproduce the prediction sample of the current picture block to obtain a reconstructed block. To further improve encoding efficiency, a method of differentially encoding a motion vector using a reference motion vector is provided later. Specifically, only the motion vector difference (MVD) is encoded. .

In order for the decoder and encoder to use the same reference picture block, the encoder needs to send the motion information of each picture block to the decoder within the bitstream. If the encoder directly encodes the motion vector of each picture block, large transmission resources are consumed. The motion vectors of spatially neighboring picture blocks are strongly correlated, and the motion vector of the current picture block can be predicted based on the motion vector of the encoded neighboring picture block. The motion vector obtained through prediction is called MVP, and the difference between the current picture block and MVP is called MVD.

In the video coding standard H.264, multiple reference frame prediction is used in the motion estimation process to improve prediction precision. Specifically, a buffer is created to store multiple reconstructed frames, and all reconstructed frames within that buffer are searched for optimal reference picture blocks for motion compensation, thereby better eliminating temporal redundancy. You can. In the video coding standard H.264, two butters are used for inter prediction: Reference Frame List 0 (Reference List 0) and Reference Frame List 1 (Reference List 1). The reference frame in which the optimal reference block in each list is located is indicated by the index value, that is, ref_idx_l0 and ref_idx_l1. In each reference frame list, the motion information of the reference picture block includes a reference frame index value (ref_idx_l0 or ref_idx_l1), MVP flag, and MVD. The decoder can find the correct reference picture block within the selected reference frame based on the reference frame index value, MVP flag, and MVD.

Currently, inter prediction modes frequently used in the HEVC standard are Advanced Motion Vector Prediction (AMVP), Merge mode, and non-translational motion model prediction mode.

In AMVP mode, the encoder constructs a candidate motion vector list using the motion vectors of encoded picture blocks that are spatially and temporally adjacent to the current picture block, and calculates the optimal motion vector in the candidate motion vector list with a rate-distortion cost. Based on the cost, the MVP of the current picture block is determined. Additionally, the encoder performs motion search in the neighbors centered on the MVP to obtain the motion vector of the current picture block. The encoder transmits the index value of the MVP in the candidate motion vector list (i.e., MVP flag), the reference frame index value, and the MVD to the decoder.

In merge mode, the encoder constructs a candidate motion information list using the motion information of the encoded picture block that is spatially or temporally adjacent to the current picture block, and selects the candidate motion information as the motion information of the current picture block based on the rate-distortion cost. Determine optimal motion information within the motion information list. The encoder transmits the index value of the position of optimal motion information in the candidate motion information list to the decoder.

In the non-switched motion model prediction mode, the encoder and decoder use the same motion model to derive motion information of all subblocks of the current picture block and perform motion compensation based on the motion information of all bus blocks to obtain a predicted picture block. do. This improves prediction efficiency. Motion models frequently used by encoders and decoders are the 4-parameter affine model, 6-parameter affine model, or 8-parameter bilinear model.

For example, a 4-parameter affine transformation model can be represented by the coordinates of two samples and the motion vectors of the two samples relative to the sample in the upper left corner of the current picture block. Here, samples used to represent motion model parameters are called control points. The sample in the upper left corner (0,0) of the current picture block and the sample in the upper right corner (W,0) of the current picture block are the control points, and the motion vectors of the samples in the upper left corner of the constitutional picture block and the upper right coder are respectively and , and the motion information of each subblock of the current picture block is obtained according to the following reception (1). In reception (1) below, is the coordinate of the subblock for the sample in the upper left corner of the current picture block, is the motion vector of that subblock, and W is the width of the current picture block.

(One)

For example, a 6-parameter affine transformation model is expressed using the coordinates of 3 samples and the motion vector of 3 samples for the sample in the upper left corner of the current picture block. A sample from the upper left corner (0,0) of the current picture block, a sample from the upper right corner (W,0) of the current picture block, and a sample from the lower left corner (0,H) of the current picture block, and a sample from the upper left corner of the current picture block. , the motion vectors of the samples in the upper right corner and lower left corner are respectively, , , and If so, the motion information of each subblock of the current picture block is obtained according to the following equation (2). In the following formula (2), is the coordinate of the subblock for the sample of the upper left corner of the current picture block, is the motion vector of that subblock, and W and H are the width and height of the current picture block, respectively.

(2)

For example, an 8-parameter bilinear model can be expressed using the coordinates of four samples for the sample of the upper left corner of the current picture block and the motion vectors of the four samples. A sample of the upper left corner (0,0) of the current picture block, a sample of the upper right corner (W,0) of the current picture block, a sample of the lower left corner (0,H) of the current picture block, and a sample of the lower right corner of the current picture block ( The samples of W, H) are the control points, and the motion vectors of the samples of the upper left corner, upper right corner, lower left corner, and lower right corner of the current picture block are respectively, , , , and If so, the motion information of each subblock of the current picture block is obtained according to the following equation (3). In the following formula (3), is the coordinate of the subblock for the sample of the upper left corner of the current picture block, is the motion vector of that subblock, and W and H are the width and height of the current picture block, respectively.

(3)

In any of the above-described inter prediction modes, it can be seen that if inter prediction is bidirectional inter prediction, the encoder must send motion information of each picture block in each direction to the decoder. As a result, motion information occupies relatively large transmission resources. This reduces effective use of transmission resources, transmission rate, and coding compression efficiency.

To solve this problem, this application provides a two-way inter prediction method. In this two-way inter prediction method, the encoder sends the motion information of the current picture block in the first direction to the decoder, and the decoder receives the motion information of the current picture block in the first direction, and then sends the motion information of the current picture block in the first direction to the decoder. Motion information of the current picture block in the second direction is calculated based on motion information of the picture block. In this way, prediction samples of the current picture block may be calculated based on motion information of the current picture block in the first direction and motion information of the current picture block in the second direction.

The bidirectional inter prediction method provided in this application is performed by a bidirectional inter prediction device, a video coding device, a video codec, or a device with another video coding function.

The bidirectional inter prediction method provided in this application is applicable to a video coding system. In the video coding system, the video encoder 100 and the video decoder 200 are configured to calculate motion information of the current picture block according to the example of the bidirectional inter prediction method provided in this application. Specifically, the motion information of the current picture block in the second direction is calculated based on the motion information of the current picture block in the first direction, so that the prediction samples of the current picture block are calculated based on the motion information of the current picture block in the first direction. information and motion information of the current picture block in the second direction. In this way, only motion information of the current picture block in the first direction needs to be transmitted between the video encoder 100 and the video decoder 200. This effectively improves transmission resource utilization and coding compression efficiency.

Figure 1 shows the structure of the video coding system 1. As shown in Figure 1, the video coding system 1 includes a source device 10 and a destination device 20. Source device 10 generates encoded video data. The source device 10 is also called a video encoding device or video encoding device. Destination device 20 decodes the encoded video data generated by source device 10. The destination device 20 is also called a video decoding device or video decoding device. The source device 10 and/or the destination device 20 may include at least one processor and a memory connected to the at least one processor. Memory may be, but is not limited to, ROM, RAM, EEPROM, flash memory, or any other form of media configured to store the necessary program code in the form of data structures or instructions that can be accessed by the computer. This is not particularly limited to this application.

Source device 10 and destination device 20 may include desktop computers, mobile computing devices, notebook (e.g., laptop) computers, tablet computers, set-top boxes, handheld telephones such as smartphones, television sets, cameras, display devices, It may include a variety of devices, including digital media players, video game consoles, vehicle-mounted computers, or similar devices.

Destination device 20 may receive encoded video data from source device 10 via link 30. Link 30 may include one or more media and/or devices capable of transmitting encoded video data from source device 10 to destination device 20. For example, link 30 may include one or more communication media that allows source device 10 to transmit encoded video data directly to destination device 20 in real time. In this example, source device 10 may modulate encoded video data according to a communication standard (e.g., a wireless communication protocol) and transmit the modulated video data to destination device 20. The one or more communication media may be wireless and/or wired, such as radio frequency (RF) spectrum, or one or more physical transmission cables. One or more communication media may form part of a packet-based network, such as a LAN, WAN, or global network (such as the Internet). One or more communication media may include a router, switch, base station, or other device that implements communication from source device 10 to destination device 20.

In another example, encoded video data may be output to storage device 40 through output interface 140. Likewise, encoded video data may be accessed from storage device 40 via input interface 240. Storage device 40 may include any type of locally accessible data storage medium, such as a Blu-ray disk, DVD, CD-ROM, flash memory, or other suitable digital storage medium configured to store encoded video data.

In another example, storage device 40 may correspond to a file server or other intermediate storage device that stores encoded video data generated by source device 10. In this example, destination device 20 may obtain stored video data from storage device 40 through streaming transmission or downloading. The file server may be any server capable of storing encoded video data and transmitting the encoded video data to the destination device 20. For example, file servers may include WWW servers (such as those used for websites), FTP servers, NAS devices, and local disk drives.

Destination device 20 may access the encoded video data over any standard data connection (eg, an Internet connection). Exemplary types of data connections include wireless channels or wired connections (eg, cable modems) suitable for accessing encoded video data stored on a file server, or a combination thereof. Encoded video data may be transmitted streaming from a file server, via downloading, or a combination thereof.

The two-way inter prediction method of the present application is not limited to wireless application scenarios. For example, the two-way inter prediction method of the present application may be used in the following applications: over-the-air television broadcasting, cable television transmission, satellite television transmission, streaming video transmission (e.g., via the Internet), and data storage media. It can be applied to video coding to support a number of multimedia applications, such as encoding of video data stored in a data storage medium, decoding of video data stored in a data magnetic medium, or other applications. In some examples, video coding system 1 may be configured to support one-way or two-way video transmission, and may be configured to support applications such as streaming video transmission, video playback, video broadcasting, and/or video telephony.

It should be noted that the video coding system 1 shown in FIG. 1 is only an example of a video coding system and does not limit the video coding system in this application. The bidirectional inter prediction method provided in this application can also be applied to scenarios where there is no data communication between the encoding device and the decoding device. In other examples, the video data to be encoded or encoded video data may be retrieved from local memory, transmitted over a network in a streaming manner, or so forth. The video decoding device may also obtain encoded video data from memory and decode the encoded video data.

In Figure 1, the source device 10 includes a video source 101, a video encoder 102, and an output interface 103. In some examples, output interface 103 may include a regulator/demodulator (modem) and/or transmitter. Video source 101 may be a video imaging device (e.g., a camera), a video archive containing pre-imaged video data, and/or a computer graphics system for generating video data, or a combination of these video data sources. may include.

Video encoder 102 may encode video data from video source 101. In some examples, source device 10 transmits the encoded video data directly to destination device 20 via output interface 103. In another example, otherwise encoded video data may be stored in storage device 40 so that destination device 20 can later access the encoded video data for decoding and/or playback.

In the example of Figure 1, destination device 20 includes a display device 201, a video decoder 202, and an input interface 203. In some examples, input interface 203 includes a receiver and/or modem. Input interface 203 may receive encoded video data via link 30 and/or from storage device 40 . The display device 201 may be integrated with the destination device 20 or may be placed external to the destination device 20 . Typically, the display device 201 displays decoded video data. Display device 201 may include several types of display devices, such as LCD, plasma display, organic light emitting diode display, or any type of display device.

Optionally, video encoder 102 and video decoder 202 may be integrated with an audio encoder and an audio decoder, respectively, and a suitable multiplexer-demultiplexer to encode both audio and video within a common data stream or separate data streams. It may include units or other hardware and software.

The video encoder 102 and the video decoder 202 include at least one microprocessor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), and discrete logic. logic), hardware, or any combination thereof. If the bidirectional inter prediction method provided in the present application is implemented using software, instructions used for the software are stored in a suitable non-volatile computer-readable storage medium, and at least one processor executes the instructions in hardware. Used to implement the application. Any of the above (including hardware, software, combinations of hardware and software, etc.) may be considered at least one processor. Video encoder 102 may be included within an encoder, video decoder 202 may be included within a decoder, and the encoder or decoder may be part of an encoder/decoder (codec) combination within a corresponding device.

In the present application, the video encoder 102 and the video decoder 202 may perform operations according to a video compression standard (eg, HEVC) or may perform operations according to other industry standards. This is not particularly limited in this application.

The video encoder 102 performs bidirectional motion estimation on the current picture block, determines motion information of the current picture block in the first direction, and generates a second motion information based on the motion information of the current picture block in the first direction. It is configured to calculate motion information of the current picture block in the direction. Here, the video encoder 102 determines a predicted picture block of the current picture block based on motion information of the current picture block in the first direction and motion information of the current picture block in the second direction. In addition, the video encoder 102 performs operations such as transformation and quantization on the residual between the current picture block and the prediction picture block of the current picture block to generate a bitstream, and sends this bitstream to the video decoder. Send to (202). The bitstream includes motion information of the current picture block in the first direction and instruction information used to instruct the second motion information to be determined based on the first motion information. This indication information may be indicated using different identifiers. For how to display instruction information, please refer to the description below.

Optionally, the method used by video encoder 102 to calculate motion information of the current picture block in the second direction based on motion information of the current picture block in the first direction is: video encoder 102 determine the motion vector of the current picture block in the second direction based on the motion vector of the current picture block in the first direction; Or, the video encoder 102 determines the motion vector difference of the current picture block in the second direction based on the motion vector difference of the current picture block in the first direction, and the motion vector difference of the current picture block in the second direction and determining the motion vector of the current picture block in the second direction based on the predicted motion vector of the current picture block in the second direction.

See Figure 4. The video decoder 202: obtains a bitstream, parses the bitstream, and determines second motion information based on first motion information, that is, based on motion information in one direction and motion information in another direction. Obtains instruction information used to determine whether to derive and calculate motion information (S400) - where the first motion information is motion information of the current picture block in the first direction, and the second motion information is the motion information in the second direction. This is the motion information of the current picture block, and the first direction and the second direction are different -; Obtain first motion information (S401); Determine second motion information based on the obtained first motion information (S402); It is configured to determine a prediction sample of the current picture block based on the first motion information and the second motion information (S403).

The method used by the video decoder 202 to calculate motion information of the current picture block in the second direction based on the motion information of the current picture block in the first direction is: determine the motion vector of the current picture block in the second direction based on the motion vector of the current picture block in; Or, the video decoder 202 determines the motion vector difference of the current picture block in the second direction based on the motion vector difference of the current picture block in the first direction, and the motion vector difference of the current picture block in the second direction and determining the motion vector of the current picture block in the second direction based on the predicted motion vector of the current picture block in the second direction.

Figure 2 is a schematic structural diagram of a video encoder 102 according to an embodiment of the present application. As shown in Figure 2, video encoder 102 is configured to output video to post-processing entity 41. Post-processing entity 41 represents an example of a video entity capable of processing encoded video data from video encoder 102, such as a media aware network element (MANE) or a slicing device/editing device. In some cases, post-processing entity 41 may be an example of a network entity. In some video encoding systems, post-processing entity 41 and video encoder 102 may be components of separate devices. In other cases, the functions described for post-processing entity 41 may be performed by the same device including video encoder 102. In one example, post-processing entity 41 is an example of storage device 40 of FIG. 1 .

The video encoder 102 derives and calculates motion information of the current picture block in the second direction based on motion information of the current picture block in the first direction, and also provides motion information of the current picture block in the first direction and A predictive picture block of the current picture block is determined based on motion information of the current picture block in the second direction, thereby completing bidirectional inter prediction encoding.

As shown in Figure 2, the video encoder 102 includes a converter 301, a quantizer 302, an entropy encoder 303, a filter 306, a memory 307, a prediction processing unit 308, and a subtractor ( 312). Prediction processing unit 308 includes an intra predictor 309 and an inter predictor 310. To reconstruct picture blocks, video encoder 102 also includes an inverse quantizer 304, an inverse transformer 305, and a summer 311. Filter 306 may be specified to represent one or more loop filters, such as a deblocking filter, an adaptive loop filter, and a sample adaptive offset filter.

Memory 307 stores video data encoded by components of video encoder 102. Video data stored in memory 307 may be obtained from video source 101. Memory 307 may be a reference picture memory that stores reference video data used by video encoder 102 to encode video data in intra or inter mode. Memory 307 may be DRAM, including synchronous RAM (SDRAM), magnetoresistive RAM (MRAM), resistive RAM (RRAM), or other types of memory devices.

Video encoder 102 receives video data and stores the video data in video data memory. The partitioning unit divides the video data into several picture blocks, and these picture blocks are further divided into smaller blocks, such as picture blocks according to a quad-tree structure or binary-tree structure. It is a division. This division may also include division into slices, tiles, or other larger units. The video encoder 102 is typically a component for encoding picture blocks within a video slice to be encoded. A slice is divided into multiple picture blocks (and also into sets of picture blocks, also called tiles).

The intra predictor 309 in the prediction processing unit 308 may perform intra prediction encoding for the current picture block relative to one or more neighboring picture blocks within the same frame or slice as the current picture block to remove spatial redundancy. You can. The inter predictor 310 in the prediction processing unit 308 may perform inter prediction encoding on the current picture block against one or more prediction picture blocks in one or more reference pictures to remove temporal redundancy.

The prediction processing unit 308 provides the obtained picture blocks, intra-coded and inter-coded, for the subtractor 312 to generate a residual block, and the encoded block to be used as a reference picture by the summer 311. A residual block can be provided to reconstruct.

After the prediction processing unit 308 generates a prediction picture block of the current picture block through inter-prediction and intra-prediction, the video encoder 102 generates a residual picture block by subtracting the prediction picture block from the current picture block to be encoded. Create. Subtractor 312 represents one or more components that perform this subtraction operation. The residual video data in the residual block is included in one or more transform units (TUs) and applied to the transformer 301. Transformer 301 converts the residual video data into residual transform coefficients through a transform such as discrete cosine transform (DCT) or a conceptually similar transform. The converter 301 converts the residual video data from the sample value domain to a transform domain, such as a frequency domain.

The converter 301 sends the obtained transform coefficient to the quantizer 302. Quantizer 302 quantizes the transform coefficients to further reduce the bit rate. In some examples, quantizer 302 also scans a matrix containing quantized transform coefficients. Alternatively, the entropy encoder 303 may perform scanning.

After quantization, the entropy encoder 303 performs entropy coding on the quantized transform coefficient. For example, the entropy encoder 303 may perform context-adaptive variable-length coding (CAVLC), context-based adaptive binary arithmetic coding (CABAC), or other entropy coding methods or techniques. After the entropy encoder 303 performs entropy coding, the encoded bitstream can be sent to the video decoder 202, or archived for later sending or for later retrieval by the video decoder 202. there is. The entropy encoder 303 may also perform entropy coding on syntactic elements of the current picture block to be encoded.

The inverse quantizer 304 and the inverse transformer 305 perform inverse quantization and inverse transformation, respectively, to reconstruct a residual block within the sample domain, for example, which is used as a reference block of a reference picture. The summer 311 adds the reconstructed residual block to the predicted picture block generated by the inter predictor 310 or the intra predictor 309 to reconstruct the reconstructed picture block. A predicted picture block of a picture block may be obtained by processing (eg, processing such as interpolating) a reference picture block of the picture block.

Other structural variations of video encoder 102 may be used to encode the video stream. For example, for some picture blocks or picture frames, video encoder 102 can quantize the residual signal directly, so that processing by transformer 301 and inverse transformer 305 is not necessary. Alternatively, for some picture blocks or picture frames, video encoder 102 does not generate residual data, and thus transformer 301 and quantizer 302, inverse quantizer 304, and inverse transformer 305 ) is no longer needed. Alternatively, video encoder 102 can directly store the reconstructed picture block as a reference block, thereby eliminating the need for processing by filter 306. Alternatively, quantizer 302 and inverse quantizer 304 may be combined in video encoder 102.

Figure 3 is a schematic structural diagram of a video decoder 202 according to an embodiment of the present application. As shown in Figure 3, the video decoder 202 includes an entropy decoder 401, an inverse quantizer 402, an inverse transformer 403, a filter 404, a memory 405, a prediction processing unit 406, and a summer 409. The prediction processing unit 406 includes an intra predictor 407 and an inter predictor 408. In some examples, video decoder 202 may perform a decoding process that is roughly reverse the encoding process described for video encoder 102 in Figure 2.

In the decoding process, video decoder 202 receives a bitstream from video encoder 102. Video decoder 202 may receive video data from network entity 42 and optionally store the video data in video data memory (not shown). Video data memory stores video data, such as an encoded bitstream, to be decoded by components of video decoder 202. Video data stored in the video data memory may be obtained from a local video source, such as a camera or storage device 40, for example, through wired or wireless network communication, or by accessing a physical data storage medium. Although the video data memory is not shown in FIG. 3, the video data memory and memory 405 may be the same memory or may be separately configured memories. Each of the video data memory and memory 405 may be constructed by any one of several types of memory devices, such as DRAM, including SDRAM, MRAM, RRAM, or other types of memory devices. In various examples, the video data memory may be integrated on a chip with other components of video decoder 202, or may be located off-chip relative to other components.

Network entity 42 may be, for example, a server, MANE, video editor/slicer, or other similar device configured to implement one or more of the techniques described above. Network entity 42 may or may not include a video encoder, such as video encoder 102, for example. Network entity 42 sends a bitstream to video decoder 22, and network entity 42 may implement some of the techniques described in this application. In some video decoding systems, network entity 42 and video decoder 202 may be components of separate devices. In other cases, the functions described for network entity 42 may be performed by the same device including video decoder 202. In some cases, network entity 42 may be an example of storage device 40 of FIG. 1 .

The entropy decoder 401 of the video decoder 202 performs entropy decoding on the bitstream, generating quantized coefficients and some syntax elements. Entropy decoder 401 passes syntax elements to filter 404. Video decoder 202 may receive syntax elements or a syntax element at the video slice level and/or at the picture block level. In the present application, as an example, a syntactic element may include indication information related to the current picture block, and the indication information is used to instruct determining the second motion information based on the first motion information. Additionally, in some examples, video encoder 102 may transmit a signal notifying certain syntax elements that indicate whether to determine second motion information based on first motion information.

The inverse quantizer 402 performs inverse quantization on the quantized transform coefficients provided in the bitstream and decoded by the entropy decode 401. The inverse quantization process includes: determining the quantization degree to be applied using the quantization parameter calculated by the video encoder 102 for each picture block in the video slice, and similarly determining the degree of inverse quantization to be applied. do. Inverse transform 403 performs an inverse transform, such as an inverse DCT, an inverse integer transform, or a conceptually similar inverse transform process, on the transform coefficients to generate a sample domain residual block.

The prediction processing unit 406 generates a prediction picture block for the current picture block or a prediction picture block for a subblock of the current picture block, and the video decoder 202 generates a residual block from the inverse transformer 403 into the prediction processing unit. In addition to the corresponding prediction picture block generated by 406, a reconstructed block, that is, a decoded picture block, is obtained. Summer 409 (also called reconstructor 409) represents the component that performs the addition operation. Optionally, additional filters (within or after the decoding loop) can be used to smoothen the samples or otherwise improve video quality. Filter 404 may be one or more loop filters, such as a deblocking filter, an adaptive loop filter (ALF), and a sample adaptive offset (SAO) filter.

It should be understood that the video decoder 202 of various other structures may be used to decode the bitstream. For example, for some picture blocks or picture frames, the entropy decoder 401 of the video decoder 202 does not obtain quantized coefficients through decoding, and accordingly, the inverse quantizer 402 and the inverse transformer 403 No processing is required. For example, inverse quantizer 402 and inverse transformer 403 within video decoder 202 may be integrated.

Based on the video coding system 1 shown in FIG. 1, the video encoder 102 shown in FIG. 2, and the video decoder 202 shown in FIG. 3, the bidirectional inter prediction method provided in the present application is described in more detail below. Explain clearly.

Figure 4 is a schematic flowchart of a bidirectional inter prediction method according to an embodiment of the present application. The method shown in Figure 4 is performed by a bidirectional inter prediction device. The bidirectional inter prediction device may be video decoder 202 of FIG. 1. 4 will be described using an example in which the bidirectional prediction device is the video decoder 202.

As shown in FIG. 4, the bidirectional prediction method according to an embodiment of the present application includes the following steps.

S400: The video decoder 202 parses the obtained bitstream and obtains indication information.

Optionally, video decoder 202 parses the bitstream and determines the inter prediction mode used to perform inter prediction on the current picture block of the current frame based on the values of syntactic elements within the bitstream. decide When the inter prediction mode is a bidirectional inter prediction mode, the video decoder 202 obtains indication information.

The video decoder 202 may receive the encoded bitstream transmitted by the video encoder 102 or obtain the encoded bitstream from the storage device 40.

Optionally, in this embodiment of the present application, the video decoder 202 determines the inter prediction mode used to perform inter prediction on the current picture block in the current frame, based on the value of the syntax element (inter_pred_idc). From the above description, inter prediction includes one-way inter prediction and two-way inter prediction. Optionally, if the value of the syntax element (inter_pred_idc) is 0, the video decoder 202 determines that the inter prediction mode used to perform inter prediction for the current picture block in the current frame is forward inter prediction. If the value of the syntax element (inter_pred_idc) is 1, the video decoder 202 determines that the inter prediction mode used to perform inter prediction on the current picture block in the current frame is backward inter prediction. If the value of the syntax element (inter_pred_idc) is 2, the video decoder 202 determines that the inter prediction mode used to perform inter prediction on the current picture block in the current frame is bidirectional inter prediction.

Optionally, after determining that the value of the syntax element (inter_pred_idc) is 2, the video decoder 202 obtains instruction information used to instruct the video decoder 202 to determine the second motion information based on the first motion information. The first motion information is motion information of the current picture block in the first direction, and the second motion information is motion information of the current picture block in the second direction, and the first direction and the second direction are different from each other.

In the present application, a picture block is a basic unit for performing video encoding or video decoding, for example, a coding unit (CU), or a basic unit for performing a prediction operation, for example, a prediction unit (PU). ) can be. However, this embodiment of the present application is not specifically limited to these.

When a picture block is a basic unit for performing video encoding or video decoding, in this embodiment of the present application, the current picture block includes at least one subblock. Accordingly, the first motion information includes motion information for each of at least one subblock of the current picture block in the first direction, and the second motion information includes motion information for each of at least one subblock of the current picture block in the second direction. It includes motion information, and the instruction information is used to instruct to determine motion information of the subblock in the second direction based on motion information of the subblock in the first direction.

Video decoder 202 can obtain instruction information in several ways.

In a first implementation, video decoder 202 parses the first identifier. When the value of the first identifier is a preset first value, the video decoder 202 determines to parse the first motion information and determines the second motion information based on the first motion information. In other words, the video decoder 202 obtains instruction information. When the value of the first identifier is the preset eighth value, the video decoder 202 parses the bitstream to obtain the fifth identifier. When the value of the fifth identifier is a preset fifth value, the video decoder 202 determines to parse the second motion information and calculates the second motion information based on the second motion information. When the value of the fifth identifier is the preset ninth value, the video decoder 202 obtains first motion information and second motion information. The preset first value and the preset fifth value may be the same or different from each other. This is not limited to this embodiment of the present application.

For example, the first identifier is mv_derived_flag_I0, the fifth identifier is mv_derived_flag_i1, the first preset value and the preset fifth value are both 1, and the eighth preset value and the ninth preset value are 0. Video decoder 202 first parses mv_derived_flag_I0. If the value of mv_derived_flag_I0 is 1, the video decoder 202 parses the first motion information and determines the second motion information based on the first motion information. If the value of mv_derived_flag_I0 is 0, the video decoder 202 parses mv_derived_flag_I1. If the value of mv_derived_flag_I1 is 1, the video decoder 202 parses the second motion information and calculates the first motion information based on the second motion information. When both the value of mv_derived_flag_I0 and the value of mv_derived_flag_I1 are 0, the video decoder 202 parses the first motion information and the second motion information.

In a second implementation, video decoder 202 parses the second identifier. When the value of the second identifier is a preset second value, the video decoder 202 determines to calculate motion information of the current picture block using a motion information derivation algorithm. Video decoder 202 then parses the third identifier. If the value of the third identifier is a preset value, the video decoder 202 determines to parse the first motion information and determines the second motion information based on the first motion information. In other words, the video decoder 202 obtains instruction information. When the value of the third identifier is the preset sixth value, the video decoder 202 determines to parse the second motion information and calculates the first motion information based on the second motion information.

For example, the second identifier is derived_mv_flag, the third identifier is derived_mv_direction, the third preset value is 1, and the sixth preset value is 0. Video decoder 202 first parses dervied_mv_flag. If the value of derived_mv_flag is 1, the video decoder 202 determines to calculate motion information of the current picture block using a motion information derivation algorithm. If the value of derived_mv_flag is 0, the video decoder 202 parses the first motion information and the second motion information. If the value of derived_mv_direction is 1, the video decoder 202 parses the first motion information and determines the second motion information based on the first motion information. If the value of derived_mv_direction is 0, the video decoder 202 parses the second motion information and calculates the first motion information based on the second motion information.

In a third implementation, video decoder 202 parses the second identifier. If the value of the second identifier is a preset second value, the video decoder 202 determines to calculate motion information of the current picture block using a motion information derivation algorithm. Then, the video decoder 202 determines to parse the first motion information based on a preset derived direction and determines the second motion information based on the first motion information. In other words, the video decoder 202 obtains instruction information. In other words, in this implementation, “determining the second motion information based on the first motion information” is preset. If the value of the second identifier is the preset seventh value, the video decoder 202 parses the first motion information and the second motion information.

For example, the second identifier is derived_mv_flag, the second preset value is 1, and the seventh preset value is 0. Video decoder 202 parses derived_mv_flag. If the value of derived_mv_flag is 1, the video decoder 202 determines to calculate motion information of the current picture block using a motion information derivation algorithm. Additionally, the video decoder 202 determines to parse the first motion information and determines the second motion information based on the first motion information. If the value of derived_mv_flag is 0, the video decoder 202 parses the first motion information and the second motion information.

In a fourth implementation, video decoder 202 parses the fourth identifier (e.g., mv_derived_flag_I0). If the value of the fourth identifier is a preset fourth value, the video decoder 202 determines to calculate the motion information of the current picture block using the motion information derivation algorithm, and calculates the motion information of the current picture block using the first reference frame list and the second reference frame list. Calculate the variable dervied_ref_num based on . This variable represents the quantity of mirrored/linear reference frame pairs that can be constituted by a first reference frame and a second reference frame. If the number of reference frame pairs is 1, the video decoder 202 directly determines the reference frame index value. Then, the video decoder 202 parses the first motion information based on the preset derived direction and determines the second motion information based on the first motion information. In other words, the video decoder 202 obtains instruction information. The first reference frame list is a reference frame list of the current picture block in the first direction, the second reference frame list is a reference frame list of the current picture block in the second direction, and the first reference frame is a list of reference frames in the first direction. It is a reference frame of the current picture block, and the second reference frame is a reference frame of the current picture block in the second direction. In this embodiment of the present application, the reference frame index value is the number of a reference frame in the corresponding reference frame list.

For example, the sequence number of the current frame is 4, the first reference frame list is {2,0}, the second reference frame list is {6,7}, and based on Condition B or Condition C below, the first It is determined that a reference frame with a sequence number of 2 in the reference frame list and a reference frame with a sequence number of 6 in the second reference frame list can form a reference frame pair. In this case, the index value of the first reference frame and the index value of the second reference frame are both 0.

For example, the sequence number of the current frame is 4, the first reference frame list is {2,0}, the second reference frame list is {6,7}, and based on Condition B or Condition C below, the first A reference frame with a sequence number of 2 in the reference frame list and a reference frame with a sequence number of 6 in the second reference frame list may form a reference frame pair, and a reference frame with a sequence number of 0 in the first reference frame list and the second reference frame may form a reference frame pair. 2 It is determined that the reference frame with sequence number 7 in the reference frame list can also form a reference frame pair. In this case, the video decoder 202 needs to parse the reference frame index value.

Furthermore, when determining that the inter prediction mode is a bidirectional inter prediction mode, the video decoder 202 further determines whether the feature information of the current frame satisfies a preset condition. Here, if the feature information of the current frame satisfies a preset condition, the video decoder 202 obtains indication information. Specifically, the process in S401 is as follows: the video decoder 202 obtains the indication information when it is determined that the inter prediction mode is a bidirectional inter prediction mode and the feature information of the current frame satisfies the first preset condition.

The feature information of the current frame includes at least one of a sequence number, a temporal level ID (TID), or a quantity of a reference frame. The bitstream obtained by the video decoder 202 includes a sequence parameter set (SPS), a picture parameter set (PPS), a slice header, or a slice segment header. , and encoded picture data. Then, the video decoder 202 parses the bitstream to obtain feature information of the current frame.

Preset conditions include at least one of the following conditions:

Condition A: The current picture block has at least two reference frames.

Condition B: The sequence number of the current frame, the sequence number of the first reference frame, and the sequence number of the second reference frame satisfy the following formula:

In this formula, POC_Cur represents the sequence number of the current frame, POC_listX represents the sequence number of the first reference frame, POC_listY represents the sequence number of the second reference frame, and the first reference frame is the current picture in the first direction. It is a reference frame of the block, and the second reference frame is a reference frame of the current picture block in the second direction.

Condition C: The sequence number of the current frame, the sequence number of the first reference frame, and the sequence number of the second reference frame satisfy the following formula:

In this formula, POC_Cur represents the sequence number of the current frame, POC_listX represents the sequence number of the first reference frame, POC_listY represents the sequence number of the second reference frame, and the first reference frame is the current picture in the first direction. It is a reference frame of the block, and the second reference frame is a reference frame of the current picture block in the second direction.

Condition D: The TID of the current frame is equal to or greater than the preset value.

In this embodiment of the present application, the preset condition may be preset or may be specific to a parameter set such as a higher layer syntax, such as SPS, PPS, slice header, or slice segment header. This is not limited to this embodiment of the present application.

Specifically, in condition B (or condition C), the video decoder 202 obtains one reference frame sequence number from each of the first reference frame list and the second reference frame list, and combines the obtained reference frame sequence number and the current frame Determine whether the sequence number satisfies condition B or condition C. When condition B (or condition C) is met, instruction information is obtained.

In this embodiment of the present application, when the inter prediction mode is a bidirectional inter prediction mode and it is determined that the feature information of the current frame satisfies the preset condition, the method used by the video decoder 202 to obtain the indication information is , is the same as the method that the video decoder 202 uses to obtain indication information when determining that the inter prediction mode is a bidirectional inter prediction mode.

Based on the above description, Table 1 shows the instructions in the first implementation when the video decoder 202 determines that the inter prediction mode is a bidirectional inter prediction mode and the feature information of the current frame satisfies the preset condition. This is a syntac table used when obtaining information.

In Table 1, x0 and y0 represent the horizontal coordinate offset and vertical coordinate offset of the subblock in the current picture block with respect to the upper left corner of the current picture block, respectively, nPbW represents the width of the current picture block, and nPbH is the width of the current picture block. indicates the height of If the value of inter_pred_idc[x0][y0] is PRED_L0, this indicates that inter prediction of the current subblock is forward prediction. If the value of inter_pred_idc[x0][y0] is PRD_L1, this indicates that inter prediction of the current subblock is backward prediction. If the value of inter_pred_idc[x0][y0] is PRED_BI, this indicates that inter prediction of the current subblock is bidirectional prediction.

For bidirectional inter prediction (i.e. inter_pred_idc[x0][y0]==PRED_BI), if the preset condition(s) are met, mb_derived_flag_I0[x0][y0] is parsed. If the value of mv_derived_flag_I0 is not the preset first value, mb_derived_flag_I1[x0][y0] is parsed. If the value of mv_derived_flag_I0 is a preset first value or the value of mv_derived_flag_I1[x0][y0] is a preset fifth value, the motion information of the subblock of the current picture block is determined, specifically the reference frame index value ref_idx_l0[x0 ][y0], motion vector predictor flag mvp_l0_flag[x0][y0], and motion vector difference mvd_coding(x0,y0,0) are determined.

Table 1

prediction_unit(x0, y0, nPbW, nPbH) {

...

/* motion vector coding */

if(slice_type==B)

inter_pred_idc[x0][y0]

if(inter_pred_idc[x0][y0]==PRED_L0) {

if( num_ref_idx_l0_active_minus1 > 0 )

ref_idx_l0[x0][y0]

mvd_coding(x0, y0, 0)

mvp_l0_flag[x0][y0]

}

if(inter_pred_idc[x0][y0]==PRED_L1) {

if( num_ref_idx_l1_active_minus1 > 0 )

ref_idx_l1[x0][y0]

mvd_coding(x0, y0, 1)

mvp_l1_flag[x0][y0]

}

if( inter_pred_idc[x0][y0]==PRED_BI) {

if(conditions) {

mv_derived_flag_l0[x0][y0]

if(!mv_derived_flag_l0[x0][y0]) {

mv_derived_flag_l1[x0][y0]

}

if(!mv_derived_flag_l0[x0][y0]) {

if( num_ref_idx_l0_active_minus1 > 0 )

ref_idx_l0[x0][y0]

mvd_coding(x0, y0, 0)

mvp_l0_flag[x0][y0]

}

if(!mv_derived_flag_l1[x0][y0]) {

if( num_ref_idx_l1_active_minus1 > 0 )

ref_idx_l1[x0][y0]

mvd_coding(x0, y0, 0 )

mvp_l1_flag[x0][y0]

}

}

Based on the above description, Table 2 shows indication information in the third implementation when the video decoder 202 determines that the inter prediction mode is a bidirectional inter prediction mode and that the feature information of the current frame satisfies the preset condition. This is a syntac table used when obtaining .

In Table 2, for bidirectional inter prediction (i.e. inter_pred_idc[x0][y0]==PRED_BI), if the preset condition(s) are met, derived_mv_flag[x0][y0] is parsed. If the value of derived_mv_flag[x0][y0] is a preset second value, the motion information of the subblock of the current picture block is determined, specifically, the reference frame index value ref_idx_lx[x0][y0], the motion vector predictor The flag mvp_lx_flag[x0][y0] and the motion vector difference mvd_coding(x0,y0,x) are determined.

Table 2

prediction_unit(x0, y0, nPbW, nPbH) {

...

/* motion vector coding */

if(slice_type==B)

inter_pred_idc[x0][y0]

if(inter_pred_idc[x0][y0]==PRED_L0) {

if( num_ref_idx_l0_active_minus1 > 0 )

ref_idx_l0[x0][y0]

mvd_coding(x0, y0, 0)

mvp_l0_flag[x0][y0]

}

if(inter_pred_idc[x0][y0]==PRED_L1) {

if( num_ref_idx_l1_active_minus1 > 0 )

ref_idx_l1[x0][y0]

mvd_coding(x0, y0, 1)

mvp_l1_flag[x0][y0]

}

if( inter_pred_idc[x0][y0]==PRED_BI) {

if(conditions) {

derived_mv_flag[ x0 ][ y0 ]

if(derived_mv_flag[x0][y0] ) {

if( num_ref_idx_lx_active_minus1 > 0 )

ref_idx_lx[x0][y0]

mvd_coding(x0, y0, x)

mvp_lx_flag[x0][y0]

} else {

...

}

}

Based on the above description, Table 3 shows the data in the fourth implementation when the video decoder 202 determines that the inter prediction mode is a bidirectional inter prediction mode and that the feature information of the current frame satisfies the preset first condition. This is a syntac table used when obtaining instruction information.

In Table 3, for bidirectional inter prediction (i.e. inter_pred_idc[x0][y0]==PRED_BI), if the preset condition(s) are met, derived_mv_flag[x0][y0] is parsed. If the value of derived_mv_flag[x0][y0] is a preset fourth value, derived_ref_num is determined, and if derived_ref_num is greater than 1, motion information of the subblock of the current picture block is determined. Specifically, the reference frame index value ref_idx_lx[ x0][y0], motion vector predictor flag mvp_lx_flag[x0][y0], and motion vector difference mvd_coding(x0,y0,x) are determined.

Table 3

prediction_unit(x0, y0, nPbW, nPbH) {

...

/* motion vector coding */

if(slice_type==B)

inter_pred_idc[x0][y0]

if(inter_pred_idc[x0][y0]==PRED_L0) {

if( num_ref_idx_l0_active_minus1 > 0 )

ref_idx_l0[x0][y0]

mvd_coding(x0, y0, 0)

mvp_l0_flag[x0][y0]

}

if(inter_pred_idc[x0][y0]==PRED_L1) {

if( num_ref_idx_l1_active_minus1 > 0 )

ref_idx_l1[x0][y0]

mvd_coding(x0, y0, 1)

mvp_l1_flag[x0][y0]

}

if( inter_pred_idc[x0][y0]==PRED_BI) {

if(conditions) {

derived_mv_flag[x0][y0]

if(derived_mv_flag[x0][y0] ) {

if( num_ref_idx_lx_active_minus1 > 0 && derived_ref_num > 1)

* ref_idx_lx[x0][y0]

mvd_coding(x0, y0, x )

mvp_lx_flag[x0][y0]

} else {

...

}

}

The first identifier, second identifier, third identifier, and fourth identifier may all be preset or may be specified in a higher layer syntax, e.g., in a parameter set such as SPS, PPS, slice header, or slice segment header. You can. This is not limited to this embodiment of the present application.

The video decoder 202 obtains indication information when the inter prediction mode is a bidirectional inter prediction mode and feature information of the current frame satisfies a preset condition. This improves the decoding rate of the video decoder 202 and reduces information redundancy.

S401: The video decoder 202 acquires first motion information.

Optionally, the video decoder 202 parses the bitstream to obtain an index value of the first reference frame, a first motion vector predictor flag, and a first motion vector difference. That is, first motion information is acquired. The first motion vector predictor flag is used to indicate the index value of the first predicted motion vector in the first candidate motion vector list, and the first predicted motion vector is the prediction of the current picture block in the first direction. The first motion vector difference is the difference between the first predicted motion vector and the second motion vector, and the first motion vector is the motion vector of the current picture block in the first direction.

In each of the syntax tables shown in Tables 1 to 3, the video decoder 202 determines motion information of a subblock of the current picture block in the first direction.

S402: The video decoder 202 determines second motion information based on the first motion information.

In a first implementation, the method that the video decoder 202 uses to determine the second motion information is as follows: the video decoder 202 selects the index value of the first reference frame from the first motion information; determine the sequence number of the first reference frame based on the index value of the first reference frame and the first reference frame list; calculate the sequence number of the second reference frame based on the sequence number of the first reference frame and the sequence number of the current frame according to a preset formula; determine the index value of the second reference frame based on the sequence number of the second reference frame and the second reference frame list; Second motion information is determined based on the index value of the second reference frame and the first motion information.

Here, the preset formula is It can be. POC_Cur represents the sequence number of the current frame, POC_listX represents the sequence number of the first reference frame, and POC_listY represents the sequence number of the second reference frame.

For example, the sequence number of the current frame is 4, the sequence number of the first reference frame is 2, the second reference frame list is [6,8], and the formula If the sequence number of the second reference frame is determined to be 6, the video decoder 202 determines that the index value ref_IY_idx of the second reference frame is 0.

Optionally, an alternatively preset formula It can be. If a plurality of reference frame sequence numbers in the second reference frame list satisfy this formula, the video decoder 202 first selects the minimum Choose a reference frame with , and then find the minimum By selecting a reference frame with , the index value of the second reference frame is determined. abs is an absolute value function.

For example, the sequence number of the current frame is 4, the sequence number of the first reference frame is 2, the second reference frame list is [5,7,8], and the formula Accordingly, if the sequence number of the second reference frame is determined to be 5, the video decoder 202 determines that the index value ref_IY_idx of the second reference frame is 0.

Optionally, a preset formula may alternatively be: It can be. If a plurality of reference frame sequence numbers in the second reference frame list satisfy this formula, the video decoder 202 first selects the minimum Choose a reference frame with , and then find the minimum By selecting a reference frame with , the index value of the second reference frame is determined. abs is an absolute value function.

For example, the sequence number of the current frame is 4, the sequence number of the first reference frame is 2, the second reference frame list is [3,2,1,0], and the formula Accordingly, if the sequence number of the second reference frame is determined to be 3, the video decoder 202 determines that the index value ref_IY_idx of the second reference frame is 0.

Optionally, a preset formula may alternatively be: , and It can be. In this case, the method that the video decoder 202 uses to determine the index value of the second reference frame is specifically as follows: Calculate the first sequence number based on the sequence number of the first reference frame and the sequence number of the current frame using - where POC_Cur represents the sequence number of the current frame, and POC_listX represents the sequence number of the first reference frame. , POC_listY0 indicates the first sequence number -; When the second reference frame list includes the first sequence number, determine, as the index value of the second reference frame, the number of the reference frame indicated by the first sequence number in the second reference frame list; or if the second reference frame list does not contain the first sequence number, Calculate a second sequence number based on the sequence number of the first reference frame and the sequence number of the current frame using - where POC_listY0' represents the second sequence number -, as an index value of the second reference frame, 2 Determine the number of the reference frame indicated by the second sequence number in the reference frame list, or, if the second reference frame list does not contain the second sequence number, the formula Calculate a third sequence number based on the sequence number of the first reference frame and the sequence number of the current frame using - where POC_listY0" represents the third reference number -, and as an index value of the second reference frame, The number of the reference frame indicated by the third sequence number in the second reference frame list is determined.

In a second implementation, the method used by the video decoder 202 to determine the second motion information is as follows: the video decoder 202 parses the bitstream to obtain the index value of the second reference frame; Second motion information is determined based on the index value of the first motion information and the second reference frame. The index value of the second reference frame may be preset or specified within a parameter set, eg, within an SPS, PPS, slice header, or slice segment header. This is not limited to this embodiment of the present application.

It can be seen that in both the first and second implementations, the video decoder 202 determines the second motion information based on the first motion information and the index value of the second reference frame.

Optionally, video decoder 202 may calculate all motion information of the current picture block in the second direction, or calculate partial motion information of the current picture block in the second direction.

Hereinafter, a process by which the video decoder 202 determines the second motion information based on the index value of the first motion information and the second reference frame will be described.

Optionally, the method that the video decoder 202 uses to determine the second motion information based on the index value of the first motion information and the second reference frame is as follows: the first reference frame in the first motion information Obtain the index value of and determine the sequence number of the first reference frame based on the first reference frame list and the index value of the first reference frame; Obtain the index value of the second reference frame, and determine the sequence number of the second reference frame based on the second reference frame list and the index value of the second reference frame; determine a first motion vector (a motion vector of the current picture block in the first direction) based on the first motion vector flag and the first motion vector difference in the first motion information; The second motion vector of the second motion information is derived according to the following formula.

In the above formula, mv_IY represents the second motion vector, POC_Cur represents the sequence number of the current frame, POC_listX represents the sequence number of the first reference frame, POC_listY represents the sequence number of the second reference frame, and mv_IX represents the sequence number of the first reference frame. 1 represents a motion vector, and the second motion vector is the motion vector of the current picture block in the second direction.

The video decoder 202 builds candidate motion information in the same way that the encoder builds a candidate motion information list in AMVP mode or merge mode, and builds a candidate motion information list based on the first motion vector prediction flag. Determine the first predicted motion vector in In this way, video decoder 202 can determine the sum of the first predicted motion vector and the first motion vector difference as the first motion vector.

Optionally, if the first reference frame is a forward reference frame of the current picture block and the second reference frame is a backward reference frame of the current picture block, or if the first reference frame is a forward reference frame of the current picture block and the second reference frame is a forward reference frame of the current picture block, or if each of the first reference frame and the second reference frame is a forward reference frame of the current picture block, or if each of the first reference frame and the second reference frame is a forward reference frame of the current picture block If it is a reference frame, the video decoder 202 can immediately set mv_IY=-mv_IX.

For example, “if the first reference frame is a forward reference frame of the current picture block and the second reference frame is a backward reference frame of the current picture block” and “if the first reference frame is a backward reference frame of the current picture block and the second reference frame is is the forward reference frame of the current picture block" all formulas Expressed using or a formula It can be expressed using .

For both “if each of the first reference frame and the second reference frame is a forward reference frame of the current picture block” and “if each of the first reference frame and the second reference frame is a backward reference frame of the current picture block”, the formula It can be expressed by .

Optionally, the method that the video decoder 202 uses to determine the second motion information based on the index value of the second reference frame and the second motion information is as follows: The first motion vector in the first motion information Obtain the index value of the difference and the first reference frame, and determine the sequence number of the first reference frame based on the index value of the first reference frame and the first reference frame list; Obtain the index value of the second reference frame, determine the sequence number of the second reference frame based on the index value of the second reference frame and the second reference frame list, and determine the sequence number of the second reference frame and the second candidate prediction. determine a second predicted motion vector based on the motion vector list, where the second predicted motion vector is the predicted motion vector of the current picture block in the second direction; Derive the second motion vector difference of the second motion information according to the following formula,

- Here, mvd_IY represents the second motion vector difference, POC_Cur represents the sequence number of the current frame, POC_listX represents the sequence number of the first reference frame, POC_listY represents the sequence number of the second reference frame, and mvd_IX represents the sequence number of the first reference frame. 1 represents the motion vector difference -; Determine a second motion vector based on the second predicted motion vector and the second motion vector difference, where the second motion vector is the motion vector of the current picture block in the second direction.

Optionally, if the first reference frame is a forward reference frame of the current picture block and the second reference frame is a backward reference frame of the current picture block, or if the first reference frame is a forward reference frame of the current picture block and the second reference frame is a forward reference frame of the current picture block, or if each of the first reference frame and the second reference frame is a forward reference frame of the current picture block, or if each of the first reference frame and the second reference frame is a forward reference frame of the current picture block If it is a reference frame, the video decoder 202 can directly set mvd_IY=-mvd_IX.

for example, , or , or If , the video decoder 202 directly sets mvd_IY=-mvd_IX.

S403: The video decoder 202 determines a prediction sample of the current picture block based on the first motion information and the second motion information.

Optionally, video decoder 202 determines a first motion vector and a second motion vector at S402. In this way, the video decoder 202 determines a first reference picture block based on a first motion vector and a first reference frame list, and a second reference picture block based on the second motion vector and the second reference frame list. can be decided. Furthermore, the video decoder 202 determines a prediction sample of the current picture block based on the first reference picture block and the second reference picture block. In other words, video decoder 202 completes the motion compensation process.

The method used by the video decoder 202 to determine the prediction sample of the current picture block based on the first reference picture block and the second reference picture block may refer to any existing method. This is not particularly limited in this embodiment of the present application.

In the bi-directional inter prediction method provided in this embodiment of the present application, the video decoder 202 can obtain only first motion information from the encoded bitstream. After obtaining the first motion information, the video decoder 202 calculates second motion information based on the first motion information, and further calculates a prediction sample of the current picture block based on the first motion information and the second motion information. decide According to the method provided in the present application, motion information of each picture block in all directions no longer needs to be transmitted, which is different from the prior art. This can effectively reduce the amount of transmitted motion information, improve effective use of transmission resources, transmission rate, and coding compression efficiency.

The bidirectional inter prediction method in FIG. 4 is explained with respect to the current picture block, that is, it can be understood that inter prediction is performed on the current picture block based on AMVP mode.

The bi-directional inter prediction method provided in the present application can also be used in a non-translational motion model prediction mode, such as a 4-parameter affine transformation motion model, a 6-parameter affine transformation motion model, or an 8-parameter bilinear motion model. It can be applied. In this scenario, the current picture block includes at least one subblock, and the motion information of the current picture block includes motion information for each of all subblocks of the current picture block. The method that the video decoder 202 uses to determine the motion information of each subblock (motion information in the first direction and motion information in the second direction) is that the video decoder 202 determines the motion information of the current picture block. It is similar to the method used to make decisions.

In the non-translational motion model prediction mode, video decoder 202 uses the following equation:

Accordingly, the motion vector of the ith control point in the second direction is calculated based on the motion vector of the ith control point in the first direction.

In the above formula, mvi_IY represents the motion vector of the ith control point in the second direction, mvi_IX represents the motion vector of the ith control point in the first direction, POC_Cur represents the sequence number of the current frame, and POC_listX represents the 1 indicates the sequence number of the reference frame, and POC_listY indicates the sequence number of the second reference frame.

Accordingly, the video decoder 202 uses the following equation:

Calculate the motion vector difference of the ith control point in the second direction based on the motion vector difference of the ith control point in the first direction using .

In the above formula, mvi_IY represents the motion vector of the ith control point in the second direction, mvi_IX represents the motion vector of the ith control point in the first direction, POC_Cur represents the sequence number of the current frame, and POC_listX represents the 1 indicates the sequence number of the reference frame, and POC_listY indicates the sequence number of the second reference frame.

Compared with the video decoder 202, the video encoder 102 in this embodiment of the present application performs bidirectional motion estimation on the current picture block to determine motion information of the current picture block in the first direction, Motion information of the current picture block in the second direction is calculated based on motion information of the current picture block in the first direction. In this way, the video encoder 102 determines a predictive picture block of the current picture block based on the motion information of the current picture block in the first direction and the motion information of the current picture block in the second direction. Then, the video encoder 102 generates a bitstream by performing operations such as transformation and quantization on the residual between the current picture block and the prediction picture block of the current picture block, and sends the bitstream to the video decoder 202. . The bitstream includes motion information of the current picture block in the first direction.

Regarding the method that the video encoder 102 uses to calculate the motion information of the current picture block in the second direction based on the motion information of the current picture block in the first direction, the video decoder 202 determines the first motion A method used to determine the second motion information based on the information may be referred to. In other words, you can refer to the description of S402. Therefore, the detailed description will not be described again in this application.

In conclusion, according to the bidirectional inter prediction method provided in this application, during bidirectional inter prediction, motion information of each picture block in all directions no longer needs to be transmitted, and only motion information in one direction needs to be transmitted. As a result, the amount of transmitted motion information can be reduced, effective use of transmission resources, transmission rate, and coding compression efficiency can be improved.

One embodiment of the present application provides a bidirectional inter prediction device. The bidirectional inter prediction device may be a video decoder. Specifically, the bidirectional inter prediction device is configured to perform the steps performed by the video decoder 202 in the bidirectional inter prediction method described above. The bidirectional inter prediction device provided in the present application may include modules for the corresponding steps.

In embodiments of the present application, the bidirectional inter prediction device may be divided into functional modules based on the method examples described above. For example, each functional module can be obtained by dividing according to its corresponding function, or two or more functions can be integrated into one processing module. The integrated module may be implemented in the form of hardware or in the form of a software function module. In the embodiments of the present application, the module division is exemplary and is only a logical function division. In actual implementation, other partitioning schemes may be used.

When each function module is obtained by division according to the corresponding function, Figure 5 is a possible schematic structural diagram of the bidirectional inter prediction device in the above-described embodiment. As shown in Figure 5, the bi-directional inter prediction device 5 includes an acquisition unit 50 and a decision unit 51.

Acquisition module 50 is configured to support a bi-directional inter prediction device performing S400, S401, etc. in the embodiments described above, and/or used in other processes of the techniques described herein.

Decision unit 51 is configured to support a bi-directional inter prediction device performing S402, 403, etc. in the above-described embodiments, and/or used in other processes of the techniques described herein.

All relevant content for the steps in the above-described method embodiments can be cited in the description of the corresponding functional module. Details will not be described again here.

What is certain is that the bidirectional inter prediction device provided in this embodiment of the present application includes, but is not limited to, the above-described modules. For example, a bidirectional inter prediction device may additionally include a storage unit 52 .

The storage unit 52 is configured to store program codes and data of the bidirectional inter prediction device.

When an integrated unit is used, Figure 6 is a schematic structural diagram of a bidirectional inter prediction device provided in embodiments of the present application. As shown in FIG. 6, the bidirectional inter prediction device 6 includes a processing module 60 and a communication module 61. The processing module 60 is configured to control and manage the operation of the bi-directional inter prediction device, e.g., to perform the steps performed by the acquisition unit 50 and the decision unit 51, and/or as described herein. The techniques described are configured to perform different processes. The communication module 61 is configured to support interaction between the two-way inter prediction device and other devices. As shown in FIG. 6, the bidirectional inter prediction device may additionally include a storage module 62. The storage module 62 is configured to store program codes and data of the bi-directional inter prediction device, e.g., stored by the storage unit 52.

Processing module 60 may be a processor or controller, such as a central processing unit (CPU), general purpose processor, digital signal processor (DSP), ASIC, FPGA, or other programmable logic device, transistor logic device, hardware component, or It could be a combination of these. A processor or controller may be any of various example logical blocks, modules, or circuits described with reference to the disclosure in this application. A processor may, alternatively, be a combination for implementing computational functions, such as a combination of one or more processors, or a combination of a DSP and a microprocessor. The communication module 61 may be a transceiver, RF circuit, communication interface, etc. Storage module 62 may be memory.

All relevant content of the scenario in the above-described method embodiments can be cited for the functional description of the corresponding functional module. Therefore, the details will not be described again here.

Both the bidirectional inter prediction device 5 and the bidirectional inter prediction device 6 can perform the bidirectional inter prediction method shown in FIG. 4. Specifically, the bidirectional inter prediction device 5 and the bidirectional inter prediction device 6 may be a video decoding device or another device with a video coding function. The bidirectional inter prediction device 5 and the bidirectional inter prediction device 6 may be configured to perform picture prediction in the decoding process.

This application also provides a terminal. The terminal includes one or more processors, memory, and communication interfaces. Memory and communication interfaces are coupled to one or more processors. The memory is configured to store computer program code. Computer program code contains instructions. When one or more processors perform an instruction, the terminal performs a bidirectional inter prediction method in the embodiments of the present application.

The terminal may be a video display device, smartphone, portable computer, or other device capable of processing or displaying video.

The present application also provides a video decoder comprising a non-volatile storage medium and a central processing unit. Non-volatile storage media store executable programs. The central processing unit is coupled to a non-volatile storage medium and executes an executable program to perform the bidirectional inter prediction method in embodiments of the present application.

This application also provides a decoder. The decoder includes a bidirectional inter prediction device (bidirectional inter prediction device 5 and bidirectional inter prediction device 6) in the embodiment of the present application, and a reconstruction module. The reconstruction module is configured to determine a reconstructed sample value of the current picture block based on prediction samples obtained by the bi-directional inter prediction device.

Another embodiment of the present application provides a computer-readable storage medium. A computer-readable storage medium includes one or more program codes. This one or more program codes contain instructions. When the terminal's processor executes this program code, the terminal performs the bidirectional inter prediction method shown in FIG. 4.

In another embodiment of the present application, a computer program form is provided. A computer program product includes computer executable instructions. Computer-executable instructions are stored in a computer-readable storage medium. At least one processor of the terminal reads computer-executable instructions from a computer-readable storage medium. The at least one processor executes computer-executable instructions to enable the terminal to perform steps performed by video decoder 202 in the bi-directional inter prediction method shown in FIG. 4.

All or part of the above-described embodiments may be implemented by software, hardware, firmware, or a combination thereof. When an embodiment is implemented using a software program, the embodiment may be implemented in whole or in part in the form of a computer program product. A computer program product includes one or more computer instructions. When computer program instructions are loaded and executed on a computer, all or part of the processing procedures or functions according to embodiments of the present application are reproduced.

The computer may be a general-purpose computer, special-purpose computer, computer network, or other programmable device. Computer instructions may be stored in a computer-readable storage medium or transmitted from a computer-readable storage medium to another computer-readable storage medium. For example, computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center, over a wire (e.g., coaxial cable, fiber optic, or Digital Subscriber Line (DSL)) or It may be transmitted wirelessly (eg, infrared or microwave). A computer-readable storage medium may be any available medium that can be accessed by a computer, or may be a server or data center, a data storage device incorporating one or more available media. Usable media may be magnetic media (eg, floppy disk, hard disk, or magnetic tape), optical media (eg, DVD), semiconductor media (eg, solid state disk (SSD)), etc.

Those skilled in the art will easily understand that the above description of the implementation example shows that the division of the above-described functional modules is exemplary for the sake of simplicity and convenience of description. In actual application, the above-described functions can be assigned to different functional modules and implemented according to requirements. That is, the internal structure of the device may be divided into different functional modules to implement all or part of the above-described functions.

It should be understood that in the various embodiments provided in this application, the disclosed devices and methods may be implemented in other ways. For example, the device embodiments described above are merely examples. For example, module or unit division is just a logical function division and may be divided differently in actual implementation. For example, multiple units or components may be combined or integrated into another device, or some features may be ignored or not performed. Additionally, the interconnections or direct couplings or communication connections shown or described may be implemented via any interface. Indirect coupling or communication connections between devices or units may be implemented in electrical, mechanical or other forms.

Units described as separate parts may or may not be physically separated, and parts indicated as units may be one or more physical units, located in one location, or distributed in different locations. All or part of the units may be selected according to actual requirements to achieve the purpose of the technical solutions of the embodiments.

Additionally, the functional units in the embodiments of the present application may be integrated into one processing unit, each unit may physically exist independently, or two or more units may be integrated into one unit. The integrated unit may be implemented in hardware or in the form of a software functional unit.

When the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, the integrated unit may be stored in a readable storage medium. Based on this understanding, the technical solution in the embodiments of the present application essentially contributes to the prior art, or all or part of the technical solution can be implemented in the form of a software product. The software product is stored on a storage medium and includes several instructions for instructing a device (single chip microcomputer, chip, etc.) or processor to perform some or all of the steps of the methods described in the embodiments of the present application. The above-mentioned storage medium includes any medium that can store program code, such as a USB flash drive, a removable hard disk, ROM, RAM, magnetic disk, or optical disk.

The above description is only a specific implementation example of the present application and does not limit the scope of protection of the present application. Any modification or replacement within the technical scope disclosed in this application shall be included in the protection scope of this application. Therefore, the scope of protection of this application should be determined by the scope of protection of the claims.

Claims (17)

An encoding method applied to two-way inter prediction, comprising:
determining a first motion vector difference of the current picture block;
Determining a first identifier - if the value of the first identifier is a first value, the first identifier is the second motion vector difference of the current picture block. is used to indicate that it is based on a first motion vector difference, where the first motion vector difference belongs to the motion information of the current picture block in a first direction, and the second motion vector difference is in the second direction. It belongs to the motion information of the current picture block, POC_Cur represents the sequence number of the current frame, POC_listX represents the sequence number of the first reference frame, POC_listY represents the sequence number of the second reference frame, and the first reference frame is is a reference frame of the current picture block in the first direction, and the second reference frame is a reference frame of the current picture block in the second direction; and
Encoding the first identifier and the first motion vector difference into a bitstream.
Including,
The second motion vector difference is expressed by the following equation:

Obtained according to,
represents the second motion vector difference, represents the first motion vector difference. According to paragraph 1,
The step of determining the first motion vector difference of the current picture block includes:
determining a first motion vector and obtaining a first predicted motion vector; and
determining the first motion vector difference based on the first motion vector and the first predicted motion vector.
Encoding method, including. According to paragraph 2,
obtaining a second predicted motion vector;
determining a second motion vector based on the second predicted motion vector and the second motion vector difference; and
Determining a prediction sample of the current picture block based on the first motion vector and the second motion vector.
It further includes,
The first predicted motion vector and the first motion vector correspond to the first direction, and the second predicted motion vector and the second motion vector correspond to the second direction. According to paragraph 3,
The current picture block includes a first reference frame list in the first direction and a second reference frame list in the second direction,
Determining a prediction sample of the current picture block based on the first motion vector and the second motion vector includes:
Obtaining a reference frame index of the first reference frame list and a reference frame index of the second reference frame list;
determining a first reference picture block based on a reference frame index of the first reference frame list, the first motion vector, and the first reference frame list;
determining a second reference picture block based on a reference frame index of the second reference frame list, the second motion vector, and the second reference frame list; and
Determining a prediction sample of the current picture block based on the first reference picture block and the second reference picture block.
Encoding method, including. According to paragraph 1,
Before encoding the first identifier into a bitstream, determining that the sequence number of the current frame in which the current picture block is located satisfies a preset condition.
It further includes,
The preset condition is that the sequence number of the current frame is between the sequence number of the first reference frame and the sequence number of the second reference frame, the first reference frame belongs to the first reference frame list, and the second reference frame An encoding method comprising a condition that a frame belongs to the second reference frame list. According to paragraph 1,
When the value of the first identifier is a second value, determining a second motion vector difference of the current picture block and encoding another second motion vector difference into the bitstream.
An encoding method further comprising: A bidirectional inter-prediction encoding device, comprising:
an acquisition unit configured to determine a first motion vector difference of the current picture block;
a determination unit configured to determine a first identifier, wherein when the value of the first identifier is a first value, the first identifier determines that the second motion vector difference of the current picture block is It is used to indicate that the decision may be made based on the first motion vector difference in the case where the first motion vector difference belongs to the motion information of the current picture block in the first direction, and the second motion vector difference is the second motion vector difference. belongs to the motion information of the current picture block in the direction, POC_Cur represents the sequence number of the current frame, POC_listX represents the sequence number of the first reference frame, POC_listY represents the sequence number of the second reference frame, and the first the reference frame is a reference frame of the current picture block in the first direction, and the second reference frame is a reference frame of the current picture block in the second direction; and
an encoding unit configured to encode the first identifier and the first motion vector difference into a bitstream
Including,
The determination unit specifically has the following formula:

configured to obtain the second motion vector difference according to,
represents the second motion vector difference, represents the first motion vector difference, bidirectional inter prediction encoding device. In clause 7,
The acquisition unit is specifically,
determine a first motion vector, obtain a first predicted motion vector;
Bidirectional inter prediction encoding device, configured to determine the first motion vector difference based on the first motion vector and the first predicted motion vector. According to clause 8,
The acquisition unit is also configured to obtain a second predicted motion vector and determine the second motion vector based on the difference between the second predicted motion vector and the second motion vector,
The bidirectional inter prediction encoding device further includes a prediction unit configured to determine a prediction sample of the current picture block based on the first motion vector and the second motion vector,
The first predicted motion vector and the first motion vector correspond to the first direction, and the second predicted motion vector and the second motion vector correspond to the second direction. According to clause 9,
The current picture block includes a first reference frame list in the first direction and a second reference frame list in the second direction,
The prediction unit is specifically,
Obtain a reference frame index of the first reference frame list and a reference frame index of the second reference frame list;
determine a first reference picture block based on a reference frame index of the first reference frame list, the first motion vector, and the first reference frame list;
determine a second reference picture block based on a reference frame index of the second reference frame list, the second motion vector, and the second reference frame list;
Bidirectional inter-prediction encoding device, configured to determine a prediction sample of the current picture block based on the first reference picture block and the second reference picture block. In clause 7,
A determination unit configured to determine that a sequence number of a current frame in which the current picture block is located satisfies a preset condition, before the encoding unit encodes the first identifier into a bitstream,
The preset condition is that the sequence number of the current frame is between the sequence number of the first reference frame and the sequence number of the second reference frame, the first reference frame belongs to the first reference frame list, and the second reference frame Bidirectional inter-prediction encoding device, comprising a condition that a frame belongs to the second reference frame list. In clause 7,
The acquisition unit is further configured to determine a second motion vector difference of the current picture block when the value of the first identifier is a second value, and encode another second motion vector difference into the bitstream. Predictive encoding device. As a storage medium,
The storage medium includes a bitstream generated using the encoding method according to any one of claims 1 to 6. An image processing device comprising a processor, memory, communication interface, and bus,
the processor is connected to the memory and the communication interface using the bus,
The memory is configured to store instructions,
The processor is configured to execute the instruction, and when the processor executes the instruction stored in the memory, the processor is capable of performing the encoding method according to any one of claims 1 to 6. . A storage medium for storing an encoded bitstream for a video signal,
The encoded bitstream includes a plurality of syntax elements,
the plurality of syntax elements include a first identifier and a first motion vector difference,
If the value of the first identifier is the first value, the first identifier is the second motion vector difference of the current picture block. It is used to indicate that the decision may be made based on the first motion vector difference in the case where the first motion vector difference belongs to the motion information of the current picture block in the first direction, and the second motion vector difference is the second motion vector difference. belongs to the motion information of the current picture block in the direction, POC_Cur represents the sequence number of the current frame, POC_listX represents the sequence number of the first reference frame, POC_listY represents the sequence number of the second reference frame, and the first The reference frame is a reference frame of the current picture block in the first direction, and the second reference frame is a reference frame of the current picture block in the second direction,
The second motion vector difference is expressed by the following equation:

Obtained according to,
represents the second motion vector difference, represents the first motion vector difference, storage medium. delete delete